TiO2 nanosheets with highly reactive {001} facets （{001}-TiO2） have attracted great attention in the fields of science and technology because of their unique properties. In recent years, many efforts have been made ...TiO2 nanosheets with highly reactive {001} facets （{001}-TiO2） have attracted great attention in the fields of science and technology because of their unique properties. In recent years, many efforts have been made to synthesize {001}-TiO2 and to explore their applications in photocatalysis. In this review, we summarize the recent progress in preparing {001}-TiO2 using different techniques such as hydrothermal, solvothermal, alcohothermal, chemical vapor deposition （CVD）, and sol gel-based techniques. Furthermore, the enhanced efficiency of {001}-TiO2 by modification of carbon materials, surface deposition of transition metals, and non-metal doping is reviewed. Then, the applications of {001}-TiOR-based photocatalysts in the degradation of organic dyes, hydrogen evolution, carbon dioxide （CO2） reduction, bacterial disinfection, and dye-sensitized solar cells are summarized. We believe this entire review on TiO2 nanosheets with {001] facets can further inspire researchers in associated fields.展开更多
Ultrathin TiO2 nanosheets with coexposed {001}/{101} facets have attracted considerable attention because of their high photocatalytic activity. However, the charge-separated states in the TiO2 nanosheets must be exte...Ultrathin TiO2 nanosheets with coexposed {001}/{101} facets have attracted considerable attention because of their high photocatalytic activity. However, the charge-separated states in the TiO2 nanosheets must be extended to further enhance their photocatalytic activity for H2 evolution. Herein, we present a successful attempt to selectively dope lanthanide ions into the {101} facets of ultrathin TiO2 nanosheets with coexposed {001}/{101} facets through a facile one-step solvothermal method. The lanthanide doping slightly extended the light-harvesting region and markedly improved the charge-separated states of the TiO2 nanosheets as evidenced by UV-vis absorption and steady-state/transient photoluminescence spectra. Upon simulated sunlight irradiation, we observed a 4.2-fold enhancement in the photocatalytic H2 evolution activity of optimal Yb3+-doped TiO2 nanosheets compared to that of their undoped counterparts. Furthermore, when Pt nanoparticles were used as cocatalysts to reduce the H2 overpotential in this system, the photocatalytic activity enhancement factor increased to 8.5. By combining these results with those of control experiments, we confirmed that the extended charge-separated states play the main role in the enhancement of the photocatalytic H2 evolution activity of lanthanide-doped TiO2 nanosheets with coexposed {001}/{101} facets.展开更多
Anatase titanium(IV) oxide (TiO2) particles with exposed {()01) and {101) facets were prepared by hydrothermal treatment of amorphous TiO2 with H2O2- NH3 solution. Crystal phase, shape, and size of TiO2 particles are ...Anatase titanium(IV) oxide (TiO2) particles with exposed {()01) and {101) facets were prepared by hydrothermal treatment of amorphous TiO2 with H2O2- NH3 solution. Crystal phase, shape, and size of TiO2 particles are found to be greatly dependent on the ratio of H2O2-NH3 solution. The prepared TiOo particles with specific exposed crystal faces show higher photocatalytic activity for acetaldehyde decomposition than commercial spherical TiO^ particles. This result implies that recombination is prevented by spatial separation of redox sites in the particles because of selective migration of electrons and positive holes to specific exposed crystal faces and/or different reactivity of electrons and positive holes on the specific exposed crystal face.展开更多
Today,nanocrystals enclosed by high-index facets(HIFs)are attracting widely attentions of researchers due to their tremendous potential in the field of catalysis,especially in electrocatalysis,such as electro-oxidatio...Today,nanocrystals enclosed by high-index facets(HIFs)are attracting widely attentions of researchers due to their tremendous potential in the field of catalysis,especially in electrocatalysis,such as electro-oxidation of small organic molecule(such as formic acid,methanol,and ethanol),oxygen reduction reaction(ORR),hydrogen evolution reaction(HER),as well as the oxygen evolution reaction(OER).However,the practical applications of nanocrystals enclosed by HIFs still face many limitations in preparations of advanced electrocatalysts,including preparation strategy,limited life-time and stability.The development of advanced electrocatalysts enclosed with HIFs is crucial for solving these problems if the large-scale application of them is to be realized.Herein,we firstly detailedly demonstrate the identification methods of nanocrystals enclosed by HIFs,and then preparation strategies are elaborated in detail in this review.Current advanced nanocrystals enclosed by HIFs in electrocatalytic application are also summarized and we present representative achievements to further reveal the relationship of excellent electrocatalytic performance and nanocrystals with HIFs.Finally,we predict the remaining challenges and present our perspectives with regards of design strategies of improving electrocatalytic performance of Ptbased catalysts in the future.展开更多
The development of highly efficient Pt-based alloy nanocatalysts is important but remains challenging for fuel cells commercialization.Here,a new class of zigzag-like platinum-zinc (Pt-Zn) alloy nanowires (NWs) with r...The development of highly efficient Pt-based alloy nanocatalysts is important but remains challenging for fuel cells commercialization.Here,a new class of zigzag-like platinum-zinc (Pt-Zn) alloy nanowires (NWs) with rough surface and controllable composition is reported.The merits of anisotropic one-dimensional nanostructure,stable high-index facets and coordinatively unsaturated Pt sites endow the composition-optimal Pt94Zn6 NWs with a mass activity of 7.2 and 6.2 times higher than that of commercial Pt black catalysts toward methanol/ethanol oxidation,respectively.Alloying-induced d-band electron modulation and lattice strain effects weaken the adsorption strength of poisoning species,which originally enhances the catalytic activity of Pt-Zn NWs.This study provides a new perspective of Pt-Zn electrocatalysts with intrinsic mechanism for enhanced catalytic performance.展开更多
Copper–ceria(Cu O–CeO2) catalysts have been known to be very effective for the oxidation of CO, and their chemical behavior has been extensively studied during the last decades. However, the effect of different CeO2...Copper–ceria(Cu O–CeO2) catalysts have been known to be very effective for the oxidation of CO, and their chemical behavior has been extensively studied during the last decades. However, the effect of different CeO2 crystal surfaces on the catalytic activity of Cu O–CeO2 for the oxidation of CO is still unclear and should be further elucidated. In this study, we deposited 1 wt% Cu on mostly {100}-exposed CeO2 nanocubes(1 Cu Ce NC) and mostly {110}-exposed CeO2 nanorods(1 Cu Ce NR), respectively. Both 1 Cu Ce NC and 1 Cu Ce NR have been used as catalysts for the oxidation of CO and achieved 100% and 50% CO conversion at 130 ℃, respectively. The differences in the catalytic activity of 1 Cu Ce NC and 1 Cu Ce NR were analyzed using temperature-programmed reduction of H2 and temperature-programmed desorption of CO techniques. The results confirmed the excellent reducibility of the 1 Cu Ce NC catalyst, which was attributed to the weak interactions between Cu and the CeO2 support. Moreover, in situ diffuse reflectance infrared Fourier-transform spectroscopy studies indicated that the {100} planes of 1 Cu Ce NC facilitated the generation of active Cu(I) sites, which resulted in the formation of highly reactive Cu(I)-CO species during the oxidation of CO. Both the excellent redox properties and effective CO adsorption capacity of the 1 Cu Ce NC catalyst increased its catalytic reactivity.展开更多
Surface engineering is known as an effective strategy to enhance the catalytic properties of Pt-based nanomaterials.Herein,we report on surface engineering Ni-Pt nanoalloys with a facile method by varying the Ni dopin...Surface engineering is known as an effective strategy to enhance the catalytic properties of Pt-based nanomaterials.Herein,we report on surface engineering Ni-Pt nanoalloys with a facile method by varying the Ni doping concentration and oleylamine/oleicacid surfactant-mix.The alloy-composition,exposed facet condition,and surface lattice strain are,thereby manipulated to optimize the catalytic efficiency of such nanoalloys for methanol oxidation reaction(MOR).Exemplary nanoalloys including Ni_(0.69)Pt_(0.31)truncated octahedrons,Ni_(0.45)Pt_(0.55)nanomultipods and Ni_(0.20)Pt_(0.80)nanoflowers are thoroughly characterized,with a commercial Pt/C catalyst as a common benchmark.Their variations in MOR catalytic efficiency are significant:2.2 A/mgPt for Ni_(0.20)Pt_(0.80)nanoflowers,1.2 A/mgPt for Ni_(0.45)Pt_(0.55)nanomultipods,0.7 A/mgPt for Ni_(0.69)Pt_(0.31)truncated octahedrons,and 0.6 A/mgPt for the commercial Pt/C catalysts.Assisted by density functional theory calculations,we correlate these observed catalysis-variations particularly to the intriguing presence of surface interplanar-strains,such as{111}facets with an interplanar-tensile-strain of 2.6%and{200}facets with an interplanar-tensile-strain of 3.5%,on the Ni_(0.20)Pt_(0.80)nanoflowers.展开更多
Cu-based electrocatalysts have provoked much attention for their high activity and selectivity in carbon dioxide(CO_(2))conversion into multi-carbon hydrocarbons.However,during the electrochemical reaction,Cu catalyst...Cu-based electrocatalysts have provoked much attention for their high activity and selectivity in carbon dioxide(CO_(2))conversion into multi-carbon hydrocarbons.However,during the electrochemical reaction,Cu catalysts inevitably undergo surface reconstruction whose impact on CO_(2)conversion performance remains contentious.Here we report that polycrystalline Cu nanoparticles(denoted as Cu-s)with rich high-index facets,derived from Cu_(2−x)S through desulphurization and surface reconstruction,offer an excellent platform for investigating the role of surface reconstruction in electrocatalytic CO_(2)conversion.During the formation of Cu-s catalyst,the two stages of desulphurization and surface reconstruction can be clearly resolved by in situ X-ray absorption spectroscopy and OH−adsorption characterizations,which are well correlated with the changes in electrocatalytic performance.It turns out that the high CO_(2)conversion performance,achieved by the Cu-s catalyst(Faradic efficiency of 68.6%and partial current density of 40.8 mA/cm^(2)in H-cell toward C_(2)H_(4)production),is attributed to the increased percentage of high-index facets in Cu-s during the surface reconstruction.Furthermore,the operando electrochemical Raman spectroscopy further reveals that the conversion of the CO_(2)into the C_(2)H_(4)on Cu-s is intermediated by the production of*COCHO.Our findings manifest that the surface reconstruction is an effective method for tuning the reaction intermediate of the CO_(2)conversion toward high-value multicarbon(C2+)chemicals,and highlight the significance of in situ characterizations in enhancing the understanding of the surface structure and its role in electrocatalysis.展开更多
Cu-based electrocatalysts with favorable facets and Cu^(+)can boost CO_(2) reduction to valuable multicarbon products.However,the inevitable Cu^(+)reduction and the phase evolution usually result in poor performance.H...Cu-based electrocatalysts with favorable facets and Cu^(+)can boost CO_(2) reduction to valuable multicarbon products.However,the inevitable Cu^(+)reduction and the phase evolution usually result in poor performance.Herein,we fabricate CuI nanodots with favorable(220)facets and a stable Cu^(+)state,accomplished by operando reconstruction of Cu(OH)_(2) under CO_(2)-and I--containing electrolytes for enhanced CO_(2)-to-C_(2)H_(4) conversion.Synchrotron X-ray absorption spectroscopy(XAS),in-situ Raman spectroscopy and thermodynamic potential analysis reveal the preferred formation of CuI.Vacuum gas electroresponse and density functional theory(DFT)calculations reveal that CO_(2)-related species induce the exposure of the(220)plane of Cu I.Moreover,the small size of nanodots enables the adequate contact with I^(-),which guarantees the rapid formation of Cu I instead of the electroreduction to Cu^(0).As a result,the resulting catalysts exhibit a high C2H4 Faradaic efficiency of 72.4%at a large current density of 800 m A cm^(-2) and robust stability for 12 h in a flow cell.Combined in-situ ATR-SEIRS spectroscopic characterizations and DFT calculations indicate that the(220)facets and stable Cu^(+) in CuI nanodots synergistically facilitate CO_(2)/*CO adsorption and*CO dimerization.展开更多
It has been widely reported that,for faceted nanocrystals,the two adjacent facets with different band levels contribute to promoted charge separation,and provide active sites for photocatalytic reduction and oxidation...It has been widely reported that,for faceted nanocrystals,the two adjacent facets with different band levels contribute to promoted charge separation,and provide active sites for photocatalytic reduction and oxidation reaction,respectively.In such cases,only one family of facets can be used for photocatalytic hydrogen evolution.Herein,by using SrTiO_(3)nanocrystals enclosed by{023}and{001}facets as a model photocatalyst,this paper proposed a strategy to achieve the full-facets-utilization of the nanocrystals for photocatalytic hydrogen via chemically depositing Pt nanoparticles on all facets.The photo-deposition experiment of CdS provided direct evidence to demonstrate that the{023}facets which were responsible for photooxidation reaction can be function-reversed for photocatalytic hydrogen evolution after depositing Pt nanoparticles,together with the{001}facets.Thus,the full-facets-utilization led to a much-improved activity for photocatalytic hydrogen,in contrast to those SrTiO_(3)nanocrystals with only{001}facets deposited by Pt nanoparticles via a photo-deposition method.展开更多
Orthorhombic Nb_(2)O_(5)(T-Nb_(2)O_(5))is attractive for fast-charging Li-ion batteries,but it is still hard to realize rapid charge transfer kinetics for Li-ion storage.Herein,F-doped T-Nb_(2)O_(5) microflowers(F-Nb_(...Orthorhombic Nb_(2)O_(5)(T-Nb_(2)O_(5))is attractive for fast-charging Li-ion batteries,but it is still hard to realize rapid charge transfer kinetics for Li-ion storage.Herein,F-doped T-Nb_(2)O_(5) microflowers(F-Nb_(2)O_(5))are rationally synthesized through topotactic conversion.Specifically,F-Nb_(2)O_(5) are assembled by single-crystal nanoflakes with nearly 97%exposed(100)facet,which maximizes the exposure of the feasible Li^(+)transport pathways along loosely packed 4g atomic layers to the electrolytes,thus effectively enhancing the Li^(+)-intercalation performance.Besides,the band gap of F-Nb_(2)O_(5) is reduced to 2.87 eV due to the doping of F atoms,leading to enhanced electrical conductivity.The synergetic effects between tailored exposed crystal facets,F-doping,and ultrathin building blocks,speed up the Li^(+)/electron transfer kinetics and improve the pseudocapacitive properties of F-Nb_(2)O_(5).Therefore,F-Nb_(2)O_(5) exhibit superior rate capability(210.8 and 164.9 mAh g^(-1) at 1 and 10 C,respectively)and good long-term 10 C cycling performance(132.7 mAh g^(-1) after 1500 cycles).展开更多
Anatase TiO2 nanocrystals and sub-microcrystals with truncated octahedral bipyramidal morphologies were prepared by direct calcination of TiOF2 precursors. The as-prepared TiO2 samples were thoroughly characterized by...Anatase TiO2 nanocrystals and sub-microcrystals with truncated octahedral bipyramidal morphologies were prepared by direct calcination of TiOF2 precursors. The as-prepared TiO2 samples were thoroughly characterized by X-ray diffraction, Raman spectroscopy, field-emission scanning electron microscopy, N2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy, and UV-visible diffuse spectroscopy. It was found that the crystallinity, grain size, and {001}/{101} ratio of the samples can be increased by raising the calcination temperature from 500 to 800℃. The higher crystallinity and {001}/{101} facet ratio resulted in an increase in both aqueous and gas-phase photocatalytic activities, by inhibiting the recombination and separation of electrons and holes. After selecting two TiO2 samples with high crystallinity and {001}/{101} ratio, Au nanoparticles were decorated on their surfaces, and the photocatalytic activity of the resulting samples under visible light illumination was studied. It was found that the visible light-induced photocatalytic activity increased by 2.6 and 4.8 times, respectively, upon Au decoration of the samples prepared by calcination of TiOF2 at 700 and 800℃.展开更多
Localized CdS homojunctions with optimal ratio of high and low index facets are constructed to dy-namically boost H_(2)O splitting into H_(2)energy by hydrothermal method in combination with calcination.By density fun...Localized CdS homojunctions with optimal ratio of high and low index facets are constructed to dy-namically boost H_(2)O splitting into H_(2)energy by hydrothermal method in combination with calcination.By density functional theory,hall effect,and in situ diffuse reflectance infrared Fourier transform spec-troscopy,it is revealed that photo-irradiated e^(−)and h^(+)can be spatially separated and directionally trans-ferred to the reductive high-index facet{002}and oxidative low-index facet{110}of localized CdS homo-junction induced by Fermi level difference of both high and low index facets to dehydrogenate ^(∗)-OH and coupled ^(∗)-O intermediates for H_(2)and O_(2)yield,respectively,along with a solar conversion into hydrogen of 1.93%by AM 1.5 G irradiation at 65℃.The study work suggests a scientific perspective on the optimal ratio of high and low index facets to understand photo-generated charge carrier transfer dynamically and their photocatalytic principle for H_(2)O splitting reaction in kinetics.展开更多
Electroreduction of carbon dioxide into fuels and feedstocks with renewable energy is an attractive route to mitigate carbon emission and solve energy crisis.However,how to improve the selectivity of high‐value multi...Electroreduction of carbon dioxide into fuels and feedstocks with renewable energy is an attractive route to mitigate carbon emission and solve energy crisis.However,how to improve the selectivity of high‐value multicarbon products is still challenging.Here,we demonstrate that the high‐index crystalline surface of copper could be designed and obtained through a simple square‐wave potential treatment on copper nanowires,which is beneficial to improve the selectivity of multi‐carbon products,especially the reaction route towards ethylene.The Faradaic efficiency of C_(2+)products can reach nearly 60%,and hydrogen can be suppressed to below 20%.Density functional theory(DFT)calculations reveal that(311)high‐index facet can activate CO_(2) effectively and promote adsorption of the*COCOH intermediate on copper for ethylene formation,therefore improves the selectivity of ethylene and inhibits the competing hydrogen evolution reaction.This method can be extended to the design of other catalytic systems and has inspirations for other electrochemical catalytic reactions.展开更多
This study examines the relationship between job satisfaction and performance,investigating personality traits and satisfaction aspects among employees of a Federal Higher Education Institution.A questionnaire was adm...This study examines the relationship between job satisfaction and performance,investigating personality traits and satisfaction aspects among employees of a Federal Higher Education Institution.A questionnaire was administered to 658 participants,using structural equation modeling for analysis.Results highlighted that challenging work,neuroticism,and self-esteem significantly influenced overall workplace satisfaction,while general satisfaction,self-efficacy,and lack of attention were key determinants of work performance.This emphasizes the importance for managers to prioritize factors enhancing employee satisfaction,as it positively correlates with job performance.展开更多
Purpose: This study aims to explore the relationships between different facets of work task and selection and query-related behavior.Design/methodology/approach:An experiment was conducted to explore the issue. The re...Purpose: This study aims to explore the relationships between different facets of work task and selection and query-related behavior.Design/methodology/approach:An experiment was conducted to explore the issue. The researcher recruited 24 participants and assigned six simulated work task situations to each of them. Each experiment lasted around 2 hours and was recorded by the software tool Morae.Findings: Time(frequency) and time(length) are more closely related to user’s selection and query-related behavior compared to the facet ‘process’ of work task. Knowledge level of work task topic, degree of work task difficulty, and subjective work task complexity are significantly correlated with selection and query-related behavior. Work task difficulty and work task complexity are different concepts. Subjective work task complexity, work task difficulty, and knowledge of work task topic are significantly correlated with user’s selection and query-related behavior.Research limitations/implications: The limitations of this study include a small sample size,limited work task situations, and possible spurious relationships. This study has implications in informing task-based information seeking/search/retrieval research and interactive information retrieval(IIR) systems design.Originality/values: Previous studies usually did not touch upon how different facets of work tasks affected interactive activities. Some studies examining task complexity and information behavior were concerned with how work tasks affect users’ behavior at information-seeking level, rather than at information search level. This study makes contribution to interactive information retrieval,task-based information search and retrieval, and personalization of IR.展开更多
In this study, a facile alcoholysis method was developed to synthesize BiOCIxBr1_x nanoplates at room temperature and atmospheric pressure. In this route, strong acid or alkaline environment was absolutely avoided to ...In this study, a facile alcoholysis method was developed to synthesize BiOCIxBr1_x nanoplates at room temperature and atmospheric pressure. In this route, strong acid or alkaline environment was absolutely avoided to realize the high exposure of {001} crystal facets. The regular changes in XRD peaks and cell parameters as a function of the Br content strongly declared that the obtained BiOCIxBrl_x products belonged to a group of solid solutions. The 2D nanosheets with in-plane wrinkles were clearly observed in TEM images. Interestingly, as the Br content increased, band gaps of BiOCIxBr1-x solid solutions gradually decreased. The photocatalytic degradation of RhB under simulated sunlight irradiation indicated that BiOCI0.sBr0.5 had the best photocatalytic activity. From the viewpoint of crystal chemistry, the photocatalytic activity of BiOCIxBr1-x solid solutions was closely related with the exposure amount of {001} facets, interlayer spacing of （001） plane and energy-level position of valence band.展开更多
基金This work was supported by the National Basic Research Program of China （No. 2013CB632402）, and the National Natural Science Foundation of China （Nos. 51272199, 51320105001, 51372190, and 21433007）. Also, this work was financially supported by the Natural Science Foundation of Hubei Province of China （Nos. 2015CFA001 and 2014CFB164）, Deanship of Scientific Research （DSR） of King Abdulaziz University （No. 90-130-35-HiCi）, the Fundamental Research Funds for the Central Universities （Nos. WUT： 2014-VII-010, 2014-IV-058, 2014-IV-155）, Self-determined and Innova- tive Research Funds of SKLWUT （No. 2013-ZD-1）, and a WUT Start-Up Grant.
文摘TiO2 nanosheets with highly reactive {001} facets （{001}-TiO2） have attracted great attention in the fields of science and technology because of their unique properties. In recent years, many efforts have been made to synthesize {001}-TiO2 and to explore their applications in photocatalysis. In this review, we summarize the recent progress in preparing {001}-TiO2 using different techniques such as hydrothermal, solvothermal, alcohothermal, chemical vapor deposition （CVD）, and sol gel-based techniques. Furthermore, the enhanced efficiency of {001}-TiO2 by modification of carbon materials, surface deposition of transition metals, and non-metal doping is reviewed. Then, the applications of {001}-TiOR-based photocatalysts in the degradation of organic dyes, hydrogen evolution, carbon dioxide （CO2） reduction, bacterial disinfection, and dye-sensitized solar cells are summarized. We believe this entire review on TiO2 nanosheets with {001] facets can further inspire researchers in associated fields.
基金supported by the National Natural Science Foundation of China(51772041,11474046,61775024)the Natural Science Foundation of Liaoning Province(20170540190,201602191)+3 种基金the Program for Liaoning Excellent Talents in University(LNET)(LR2015016,LR2017004)the Program for Dalian Excellent Talents(2016RQ069)the Science and the Technique Foundation of Dalian(2014J11JH134,2015J12JH201)the Fundamental Research Funds for the Central Universities(wd01206)~~
文摘Ultrathin TiO2 nanosheets with coexposed {001}/{101} facets have attracted considerable attention because of their high photocatalytic activity. However, the charge-separated states in the TiO2 nanosheets must be extended to further enhance their photocatalytic activity for H2 evolution. Herein, we present a successful attempt to selectively dope lanthanide ions into the {101} facets of ultrathin TiO2 nanosheets with coexposed {001}/{101} facets through a facile one-step solvothermal method. The lanthanide doping slightly extended the light-harvesting region and markedly improved the charge-separated states of the TiO2 nanosheets as evidenced by UV-vis absorption and steady-state/transient photoluminescence spectra. Upon simulated sunlight irradiation, we observed a 4.2-fold enhancement in the photocatalytic H2 evolution activity of optimal Yb3+-doped TiO2 nanosheets compared to that of their undoped counterparts. Furthermore, when Pt nanoparticles were used as cocatalysts to reduce the H2 overpotential in this system, the photocatalytic activity enhancement factor increased to 8.5. By combining these results with those of control experiments, we confirmed that the extended charge-separated states play the main role in the enhancement of the photocatalytic H2 evolution activity of lanthanide-doped TiO2 nanosheets with coexposed {001}/{101} facets.
基金financially supported by the Programs of Japan Science and Technology Agency: Promoting Individual Research to Nature the Seeds of Future Innovation and Organizing the Unique and Innovative Network, and Advanced Catalytic Transformation Program for Carbon Utilization
文摘Anatase titanium(IV) oxide (TiO2) particles with exposed {()01) and {101) facets were prepared by hydrothermal treatment of amorphous TiO2 with H2O2- NH3 solution. Crystal phase, shape, and size of TiO2 particles are found to be greatly dependent on the ratio of H2O2-NH3 solution. The prepared TiOo particles with specific exposed crystal faces show higher photocatalytic activity for acetaldehyde decomposition than commercial spherical TiO^ particles. This result implies that recombination is prevented by spatial separation of redox sites in the particles because of selective migration of electrons and positive holes to specific exposed crystal faces and/or different reactivity of electrons and positive holes on the specific exposed crystal face.
基金financially supported by the National Natural Science Foundation of China(No.22008135)the China Postdoctoral Science Foundation(No.2020M670345)。
文摘Today,nanocrystals enclosed by high-index facets(HIFs)are attracting widely attentions of researchers due to their tremendous potential in the field of catalysis,especially in electrocatalysis,such as electro-oxidation of small organic molecule(such as formic acid,methanol,and ethanol),oxygen reduction reaction(ORR),hydrogen evolution reaction(HER),as well as the oxygen evolution reaction(OER).However,the practical applications of nanocrystals enclosed by HIFs still face many limitations in preparations of advanced electrocatalysts,including preparation strategy,limited life-time and stability.The development of advanced electrocatalysts enclosed with HIFs is crucial for solving these problems if the large-scale application of them is to be realized.Herein,we firstly detailedly demonstrate the identification methods of nanocrystals enclosed by HIFs,and then preparation strategies are elaborated in detail in this review.Current advanced nanocrystals enclosed by HIFs in electrocatalytic application are also summarized and we present representative achievements to further reveal the relationship of excellent electrocatalytic performance and nanocrystals with HIFs.Finally,we predict the remaining challenges and present our perspectives with regards of design strategies of improving electrocatalytic performance of Ptbased catalysts in the future.
基金the National Key Research and Development Program of China (No.2016YFA0200400)the National Natural Science Foundation of China (Nos.51571100,51602305, 51522212,51421002,and 51672307)+1 种基金Program for JLU Science and Technology Innovative Research Team (JLUSTIRT,2017TD-09)the Fundamental Research Funds for the Central Universities and the Graduate Innovation Fund of Jilin University.
文摘The development of highly efficient Pt-based alloy nanocatalysts is important but remains challenging for fuel cells commercialization.Here,a new class of zigzag-like platinum-zinc (Pt-Zn) alloy nanowires (NWs) with rough surface and controllable composition is reported.The merits of anisotropic one-dimensional nanostructure,stable high-index facets and coordinatively unsaturated Pt sites endow the composition-optimal Pt94Zn6 NWs with a mass activity of 7.2 and 6.2 times higher than that of commercial Pt black catalysts toward methanol/ethanol oxidation,respectively.Alloying-induced d-band electron modulation and lattice strain effects weaken the adsorption strength of poisoning species,which originally enhances the catalytic activity of Pt-Zn NWs.This study provides a new perspective of Pt-Zn electrocatalysts with intrinsic mechanism for enhanced catalytic performance.
文摘Copper–ceria(Cu O–CeO2) catalysts have been known to be very effective for the oxidation of CO, and their chemical behavior has been extensively studied during the last decades. However, the effect of different CeO2 crystal surfaces on the catalytic activity of Cu O–CeO2 for the oxidation of CO is still unclear and should be further elucidated. In this study, we deposited 1 wt% Cu on mostly {100}-exposed CeO2 nanocubes(1 Cu Ce NC) and mostly {110}-exposed CeO2 nanorods(1 Cu Ce NR), respectively. Both 1 Cu Ce NC and 1 Cu Ce NR have been used as catalysts for the oxidation of CO and achieved 100% and 50% CO conversion at 130 ℃, respectively. The differences in the catalytic activity of 1 Cu Ce NC and 1 Cu Ce NR were analyzed using temperature-programmed reduction of H2 and temperature-programmed desorption of CO techniques. The results confirmed the excellent reducibility of the 1 Cu Ce NC catalyst, which was attributed to the weak interactions between Cu and the CeO2 support. Moreover, in situ diffuse reflectance infrared Fourier-transform spectroscopy studies indicated that the {100} planes of 1 Cu Ce NC facilitated the generation of active Cu(I) sites, which resulted in the formation of highly reactive Cu(I)-CO species during the oxidation of CO. Both the excellent redox properties and effective CO adsorption capacity of the 1 Cu Ce NC catalyst increased its catalytic reactivity.
基金supported by the National Key Research and Development Program of China(No.2018YFA0703700)the National Natural Science Foundation of China(Nos.11674008,11674023,and 51971025)+1 种基金Ministry of Education,China-111 Project(No.B170003)Scientific and Technological Innovation Foundation of Shunde Graduate School,USTB(No.BK19BE024).
文摘Surface engineering is known as an effective strategy to enhance the catalytic properties of Pt-based nanomaterials.Herein,we report on surface engineering Ni-Pt nanoalloys with a facile method by varying the Ni doping concentration and oleylamine/oleicacid surfactant-mix.The alloy-composition,exposed facet condition,and surface lattice strain are,thereby manipulated to optimize the catalytic efficiency of such nanoalloys for methanol oxidation reaction(MOR).Exemplary nanoalloys including Ni_(0.69)Pt_(0.31)truncated octahedrons,Ni_(0.45)Pt_(0.55)nanomultipods and Ni_(0.20)Pt_(0.80)nanoflowers are thoroughly characterized,with a commercial Pt/C catalyst as a common benchmark.Their variations in MOR catalytic efficiency are significant:2.2 A/mgPt for Ni_(0.20)Pt_(0.80)nanoflowers,1.2 A/mgPt for Ni_(0.45)Pt_(0.55)nanomultipods,0.7 A/mgPt for Ni_(0.69)Pt_(0.31)truncated octahedrons,and 0.6 A/mgPt for the commercial Pt/C catalysts.Assisted by density functional theory calculations,we correlate these observed catalysis-variations particularly to the intriguing presence of surface interplanar-strains,such as{111}facets with an interplanar-tensile-strain of 2.6%and{200}facets with an interplanar-tensile-strain of 3.5%,on the Ni_(0.20)Pt_(0.80)nanoflowers.
基金supported in part by the National Key R&D Program of China(Nos.2017YFA0207301 and 2017YFA0403402)the National Natural Science Foundation of China(Nos.21725102,91961106,U1832156,and 22075267)+4 种基金Science and Technological Fund of Anhui Province for Outstanding Youth(No.2008085J05)Youth Innovation Promotion Association of CAS(No.2019444)Young Elite Scientist Sponsorship Program by CAST,China Postdoctoral Science Foundation(Nos.2019M652190 and 2020T130627)Users with Excellence Program of Hefei Science Center CAS(No.2020HSC-UE003)DNL Cooperation Fund,CAS(No.DNL201922).
文摘Cu-based electrocatalysts have provoked much attention for their high activity and selectivity in carbon dioxide(CO_(2))conversion into multi-carbon hydrocarbons.However,during the electrochemical reaction,Cu catalysts inevitably undergo surface reconstruction whose impact on CO_(2)conversion performance remains contentious.Here we report that polycrystalline Cu nanoparticles(denoted as Cu-s)with rich high-index facets,derived from Cu_(2−x)S through desulphurization and surface reconstruction,offer an excellent platform for investigating the role of surface reconstruction in electrocatalytic CO_(2)conversion.During the formation of Cu-s catalyst,the two stages of desulphurization and surface reconstruction can be clearly resolved by in situ X-ray absorption spectroscopy and OH−adsorption characterizations,which are well correlated with the changes in electrocatalytic performance.It turns out that the high CO_(2)conversion performance,achieved by the Cu-s catalyst(Faradic efficiency of 68.6%and partial current density of 40.8 mA/cm^(2)in H-cell toward C_(2)H_(4)production),is attributed to the increased percentage of high-index facets in Cu-s during the surface reconstruction.Furthermore,the operando electrochemical Raman spectroscopy further reveals that the conversion of the CO_(2)into the C_(2)H_(4)on Cu-s is intermediated by the production of*COCHO.Our findings manifest that the surface reconstruction is an effective method for tuning the reaction intermediate of the CO_(2)conversion toward high-value multicarbon(C2+)chemicals,and highlight the significance of in situ characterizations in enhancing the understanding of the surface structure and its role in electrocatalysis.
基金financially supported by The National Key Research and Development Program of China(2021YFA1600800)the Start-up Funding of the Huazhong University of Science and Technology(HUST)+2 种基金the Program for HUST Academic Frontier Youth Teamthe National Natural Science Foundation of China(22075092)the National 1000 Young Talents Program of China and The Innovation and Talent Recruitment Base of New Energy Chemistry and Device(B21003)。
文摘Cu-based electrocatalysts with favorable facets and Cu^(+)can boost CO_(2) reduction to valuable multicarbon products.However,the inevitable Cu^(+)reduction and the phase evolution usually result in poor performance.Herein,we fabricate CuI nanodots with favorable(220)facets and a stable Cu^(+)state,accomplished by operando reconstruction of Cu(OH)_(2) under CO_(2)-and I--containing electrolytes for enhanced CO_(2)-to-C_(2)H_(4) conversion.Synchrotron X-ray absorption spectroscopy(XAS),in-situ Raman spectroscopy and thermodynamic potential analysis reveal the preferred formation of CuI.Vacuum gas electroresponse and density functional theory(DFT)calculations reveal that CO_(2)-related species induce the exposure of the(220)plane of Cu I.Moreover,the small size of nanodots enables the adequate contact with I^(-),which guarantees the rapid formation of Cu I instead of the electroreduction to Cu^(0).As a result,the resulting catalysts exhibit a high C2H4 Faradaic efficiency of 72.4%at a large current density of 800 m A cm^(-2) and robust stability for 12 h in a flow cell.Combined in-situ ATR-SEIRS spectroscopic characterizations and DFT calculations indicate that the(220)facets and stable Cu^(+) in CuI nanodots synergistically facilitate CO_(2)/*CO adsorption and*CO dimerization.
基金supported by the National Natural Science Foundation of China(Grant Nos.52225606 and 51888103)the Fundamental Research Funds for the Central Universities,Chinathe Youth Innovation Team of Shaanxi Universities,China.
文摘It has been widely reported that,for faceted nanocrystals,the two adjacent facets with different band levels contribute to promoted charge separation,and provide active sites for photocatalytic reduction and oxidation reaction,respectively.In such cases,only one family of facets can be used for photocatalytic hydrogen evolution.Herein,by using SrTiO_(3)nanocrystals enclosed by{023}and{001}facets as a model photocatalyst,this paper proposed a strategy to achieve the full-facets-utilization of the nanocrystals for photocatalytic hydrogen via chemically depositing Pt nanoparticles on all facets.The photo-deposition experiment of CdS provided direct evidence to demonstrate that the{023}facets which were responsible for photooxidation reaction can be function-reversed for photocatalytic hydrogen evolution after depositing Pt nanoparticles,together with the{001}facets.Thus,the full-facets-utilization led to a much-improved activity for photocatalytic hydrogen,in contrast to those SrTiO_(3)nanocrystals with only{001}facets deposited by Pt nanoparticles via a photo-deposition method.
基金supported by the National Natural Science Foundation of China(No.51802163)the Natural Science Foundation of Henan Province of China(No.222300420252)the Natural Science Foundation of Henan Department of Education(No.20A480004).
文摘Orthorhombic Nb_(2)O_(5)(T-Nb_(2)O_(5))is attractive for fast-charging Li-ion batteries,but it is still hard to realize rapid charge transfer kinetics for Li-ion storage.Herein,F-doped T-Nb_(2)O_(5) microflowers(F-Nb_(2)O_(5))are rationally synthesized through topotactic conversion.Specifically,F-Nb_(2)O_(5) are assembled by single-crystal nanoflakes with nearly 97%exposed(100)facet,which maximizes the exposure of the feasible Li^(+)transport pathways along loosely packed 4g atomic layers to the electrolytes,thus effectively enhancing the Li^(+)-intercalation performance.Besides,the band gap of F-Nb_(2)O_(5) is reduced to 2.87 eV due to the doping of F atoms,leading to enhanced electrical conductivity.The synergetic effects between tailored exposed crystal facets,F-doping,and ultrathin building blocks,speed up the Li^(+)/electron transfer kinetics and improve the pseudocapacitive properties of F-Nb_(2)O_(5).Therefore,F-Nb_(2)O_(5) exhibit superior rate capability(210.8 and 164.9 mAh g^(-1) at 1 and 10 C,respectively)and good long-term 10 C cycling performance(132.7 mAh g^(-1) after 1500 cycles).
基金supported by the National Natural Science Foundation of China(51772230,51461135004)the Hubei Foreign Science and Technology Cooperation Project(2017AHB059)the Japan Society for the Promotion of Science(JSPS)for an Invitational Fellowship for Foreign Researchers(L16531)~~
文摘Anatase TiO2 nanocrystals and sub-microcrystals with truncated octahedral bipyramidal morphologies were prepared by direct calcination of TiOF2 precursors. The as-prepared TiO2 samples were thoroughly characterized by X-ray diffraction, Raman spectroscopy, field-emission scanning electron microscopy, N2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy, and UV-visible diffuse spectroscopy. It was found that the crystallinity, grain size, and {001}/{101} ratio of the samples can be increased by raising the calcination temperature from 500 to 800℃. The higher crystallinity and {001}/{101} facet ratio resulted in an increase in both aqueous and gas-phase photocatalytic activities, by inhibiting the recombination and separation of electrons and holes. After selecting two TiO2 samples with high crystallinity and {001}/{101} ratio, Au nanoparticles were decorated on their surfaces, and the photocatalytic activity of the resulting samples under visible light illumination was studied. It was found that the visible light-induced photocatalytic activity increased by 2.6 and 4.8 times, respectively, upon Au decoration of the samples prepared by calcination of TiOF2 at 700 and 800℃.
基金supported by the National Natural Science Foundation of China(No.51972177)the Natural Science Foundation of Ningbo City(No.2021J067)the SJLY2021010 of Ningbo University,Fan 3315 Plan,and Yongjiang Scholar Project.
文摘Localized CdS homojunctions with optimal ratio of high and low index facets are constructed to dy-namically boost H_(2)O splitting into H_(2)energy by hydrothermal method in combination with calcination.By density functional theory,hall effect,and in situ diffuse reflectance infrared Fourier transform spec-troscopy,it is revealed that photo-irradiated e^(−)and h^(+)can be spatially separated and directionally trans-ferred to the reductive high-index facet{002}and oxidative low-index facet{110}of localized CdS homo-junction induced by Fermi level difference of both high and low index facets to dehydrogenate ^(∗)-OH and coupled ^(∗)-O intermediates for H_(2)and O_(2)yield,respectively,along with a solar conversion into hydrogen of 1.93%by AM 1.5 G irradiation at 65℃.The study work suggests a scientific perspective on the optimal ratio of high and low index facets to understand photo-generated charge carrier transfer dynamically and their photocatalytic principle for H_(2)O splitting reaction in kinetics.
基金National Natural Science Foundation of China,Grant/Award Number:21902009National Key Research and Development Project,Grant/Award Numbers:2018YFB1502401,2018YFA0702002+2 种基金Royal Society and the Newton Fund through the Newton Advanced Fellowship Award,Grant/Award Number:NAF\R1\191294Program for Changjiang Scholars and Innovation Research Team in the University,Grant/Award Number:IRT1205Fundamental Research Funds for the Central Universities,and the longterm subsidy mechanism from the Ministry of Finance and the Ministry of Education of PRC。
文摘Electroreduction of carbon dioxide into fuels and feedstocks with renewable energy is an attractive route to mitigate carbon emission and solve energy crisis.However,how to improve the selectivity of high‐value multicarbon products is still challenging.Here,we demonstrate that the high‐index crystalline surface of copper could be designed and obtained through a simple square‐wave potential treatment on copper nanowires,which is beneficial to improve the selectivity of multi‐carbon products,especially the reaction route towards ethylene.The Faradaic efficiency of C_(2+)products can reach nearly 60%,and hydrogen can be suppressed to below 20%.Density functional theory(DFT)calculations reveal that(311)high‐index facet can activate CO_(2) effectively and promote adsorption of the*COCOH intermediate on copper for ethylene formation,therefore improves the selectivity of ethylene and inhibits the competing hydrogen evolution reaction.This method can be extended to the design of other catalytic systems and has inspirations for other electrochemical catalytic reactions.
文摘This study examines the relationship between job satisfaction and performance,investigating personality traits and satisfaction aspects among employees of a Federal Higher Education Institution.A questionnaire was administered to 658 participants,using structural equation modeling for analysis.Results highlighted that challenging work,neuroticism,and self-esteem significantly influenced overall workplace satisfaction,while general satisfaction,self-efficacy,and lack of attention were key determinants of work performance.This emphasizes the importance for managers to prioritize factors enhancing employee satisfaction,as it positively correlates with job performance.
基金sponsored by National Social Science Foundation of China(Grant No. 11BTQ009)
文摘Purpose: This study aims to explore the relationships between different facets of work task and selection and query-related behavior.Design/methodology/approach:An experiment was conducted to explore the issue. The researcher recruited 24 participants and assigned six simulated work task situations to each of them. Each experiment lasted around 2 hours and was recorded by the software tool Morae.Findings: Time(frequency) and time(length) are more closely related to user’s selection and query-related behavior compared to the facet ‘process’ of work task. Knowledge level of work task topic, degree of work task difficulty, and subjective work task complexity are significantly correlated with selection and query-related behavior. Work task difficulty and work task complexity are different concepts. Subjective work task complexity, work task difficulty, and knowledge of work task topic are significantly correlated with user’s selection and query-related behavior.Research limitations/implications: The limitations of this study include a small sample size,limited work task situations, and possible spurious relationships. This study has implications in informing task-based information seeking/search/retrieval research and interactive information retrieval(IIR) systems design.Originality/values: Previous studies usually did not touch upon how different facets of work tasks affected interactive activities. Some studies examining task complexity and information behavior were concerned with how work tasks affect users’ behavior at information-seeking level, rather than at information search level. This study makes contribution to interactive information retrieval,task-based information search and retrieval, and personalization of IR.
文摘In this study, a facile alcoholysis method was developed to synthesize BiOCIxBr1_x nanoplates at room temperature and atmospheric pressure. In this route, strong acid or alkaline environment was absolutely avoided to realize the high exposure of {001} crystal facets. The regular changes in XRD peaks and cell parameters as a function of the Br content strongly declared that the obtained BiOCIxBrl_x products belonged to a group of solid solutions. The 2D nanosheets with in-plane wrinkles were clearly observed in TEM images. Interestingly, as the Br content increased, band gaps of BiOCIxBr1-x solid solutions gradually decreased. The photocatalytic degradation of RhB under simulated sunlight irradiation indicated that BiOCI0.sBr0.5 had the best photocatalytic activity. From the viewpoint of crystal chemistry, the photocatalytic activity of BiOCIxBr1-x solid solutions was closely related with the exposure amount of {001} facets, interlayer spacing of （001） plane and energy-level position of valence band.
