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
The exposed crystal facet of TiO2 is a crucial factor influencing the gas sensing properties. TiO2 with high-energy{001}crystal facets that have higher surface energy and reactivity is expected to exhibit excellent ga...The exposed crystal facet of TiO2 is a crucial factor influencing the gas sensing properties. TiO2 with high-energy{001}crystal facets that have higher surface energy and reactivity is expected to exhibit excellent gas-sensing properties. In this paper, TiO2 nanoplates with defective{001}facets were synthesized by chemical etching via one-step hydrothermal method. We carefully explored the gas-sensing performance of TiO2 nanoplates with defective and complete{001}facets towards acetone. The results show that the sensing response of TiO2 nanoplates with complete{001}facets is 70%higher than that of defective TiO2 nanoplates, which proves that the{001}facets plays a vital role in improving the gas sensing performance of TiO2. It is speculated that the poor gas sensitivity of defective TiO2 can be contributed to fewer adsorption sites and blocked electron transfer. This work presents a more direct evidence for explaining the important role of the complete{001}crystal facets in high sensitivity of TiO2 and also provides a new insight for preparing high sensitivity sensing materials.展开更多
A facile, fluorine-free approach for synthesizing vertically aligned arrays of mesocrystaUine anatase TiO2 nanosheets with highly exposed {001} facets was developed through topotactic transformation. Unique mesocrysta...A facile, fluorine-free approach for synthesizing vertically aligned arrays of mesocrystaUine anatase TiO2 nanosheets with highly exposed {001} facets was developed through topotactic transformation. Unique mesocrystalline {001}-faceted TiO2 nanosheet arrays vertically aligned on conductive fluorine-doped tin oxide glass were realized through topotactic conversion from single-crystalline precursor nanosheet arrays based on lattice matching between the precursor and the anatase crystals. The morphology and microstructure of the {001}-faceted TiO2 nanosheets could be readily modulated by changing the reactant concentration and annealing temperature. Owing to enhanced dye adsorption, reduced charge recombination, and enhanced light scattering arising from the exposed {001} facets, in addition to the advantageous features of low-dimensional structure arrays （e.g., fast electron transport and efficient charge collection）, the obtained TiO2 nanosheet arrays exhibited superior performance when they were used as anodes for dye-sensitized solar cells （DSSCs）. Particularly, {001}-faceted TiO2 nanosheet arrays -15 μm long annealed at 500 ℃ showed a power conversion efficiency of 7.51%. Furthermore, a remarkable efficiency of 8.85% was achieved for a DSSC based on doubleqayered TiO2 nanosheet arrays -35 μm long, which were prepared by conversion from the precursor nanoarrays produced via secondary hydrothermal growth.展开更多
Nitrogen （N） and phosphorus （P） co-doped anatase TiO2 nanosheets were realized by low-temperature self-doping N-TiO2 followed by high-temperature P doping with foreign precursor. It is found that P doping process ...Nitrogen （N） and phosphorus （P） co-doped anatase TiO2 nanosheets were realized by low-temperature self-doping N-TiO2 followed by high-temperature P doping with foreign precursor. It is found that P doping process can maintain good TiO2 nanosheets morphology with exposed {001} facets. Chemical state of dopants indicates that N and P atoms replace O on O sites in TiO2 lattice. Compared with pure TiO2 and N-doped TiO2, N-P codoped TiO2 nanosheets exhibits stronger optical absorption and higher degradation rate of dye molecules in visible light regime. The enhanced photocatalytic properties are attributed to two factors. On one hand, N-P co-doping can effectively reduce band gap of TiO2 from 3.20 to 2.48 eV, leading to an enhancement of the absorption in visible light regime. On the other hand, the presence of exposed {001} facets of TiO2 nanosheets can induce the effective sepa- ration of photogenerated electrons and holes in reaction.展开更多
Anatase TiO2 with a variant percentage of exposed （001） facets was prepared under hydrothermal processes by adjusting the volume of HF, and the photocatalytic mechanism was studied from atomic-molecular scale by HRT...Anatase TiO2 with a variant percentage of exposed （001） facets was prepared under hydrothermal processes by adjusting the volume of HF, and the photocatalytic mechanism was studied from atomic-molecular scale by HRTEM and Raman spectroscopy. It was revealed that： 1） From HRTEM observations, the surface of original TiO2 with exposed （001） facets was clean without impurity, and the crystal lattice was clear and completed; however, when mixed with methylene blue （MB） solution, there were many 1 nm molecular absorbed at the surface of TiO2; after the photocatalytic experiment, MB molecules disappeared and the TiO2 lattice image became fuzzy. 2） The broken path of the MB chemical bond was obtained by Raman spectroscopy, i.e., after the irradiation of the light, the vibrational mode of C-N-C disappeared due to the chemical bond breakage, and the groups containing C-N bond and carbon rings were gradually decomposed. Accordingly, we propose that the driving force for breaking the chemical bond and the disappearance of groups is from the surface lattice distortion of TiO2 during photocatalyzation.展开更多
Photocatalytic carbon dioxide reduction reaction(CO2RR)has been considered as one of most effective ways to solve the current energy crisis and environmental problems.However,the practical application of photocatalyti...Photocatalytic carbon dioxide reduction reaction(CO2RR)has been considered as one of most effective ways to solve the current energy crisis and environmental problems.However,the practical application of photocatalytic CO2RR is largely hindered by lock of efficient catalyst.Here,hierarchical titanium dioxide(TiO2)nanostructures with a highly active{001}surface were successfully synthesized by a facile approach from metal Ti powders.The obtained hierarchical TiO2 nanostructures were composed of TiO2 nanorods,which have a diameter about 5–10 nm and a length of several micrometers.It is found that these nanorods have exposed{001}facets.On the other hand,these hierarchical TiO2 nanostructures have a good light-harvesting efficiency with the help of TiO2 nanorods component and large specific surface area.Therefore,these hierarchical TiO2 nanostructures exhibit a much better activity for photocatalytic CO2 reduction than that of commercial TiO2(P25).This high activity can be attributed to the synergistic effects of active surface,efficient charge transfer along nanorods and good light harvesting in the nanorod-hierarchical nanostructures.展开更多
A sample of sulfated anatase TiO2 with high‐energy(001)facets(TiO2‐001)was prepared by a simple one‐step hydrothermal route using SO42-as a morphology‐controlling agent.After doping ceria,Ce/TiO2‐001 was used as ...A sample of sulfated anatase TiO2 with high‐energy(001)facets(TiO2‐001)was prepared by a simple one‐step hydrothermal route using SO42-as a morphology‐controlling agent.After doping ceria,Ce/TiO2‐001 was used as the catalyst for selective catalytic reduction(SCR)of NO with NH3.Compared with Ce/P25(Degussa P25 TiO2)and Ce/P25‐S(sulfated P25)catalysts,Ce/TiO2‐001 was more suitable for medium‐and high‐temperature SCR of NO due to the high surface area,sulfation,and the excellent properties of the active‐energy(001)facets.All of these facilitated the generation of abundant acidity,chemisorbed oxygen,and activated NOx‐adsorption species,which were the important factors for the SCR reaction.展开更多
Anatase TiO2with exposed{001}facets has been deepgoingly studied for optimizing its photocatalytic activity.In this study,we synthesized N-doped TiO2 nanocrystals with exposed{001}facets by sol–gel method and solvoth...Anatase TiO2with exposed{001}facets has been deepgoingly studied for optimizing its photocatalytic activity.In this study,we synthesized N-doped TiO2 nanocrystals with exposed{001}facets by sol–gel method and solvothermal method,respectively.The physical and chemical properties of as-synthesized samples,such as morphology,crystal phase,surface elements composition,porous structure,specific surface area,and optical response,were characterized in detail.The photocatalytic performances of all samples were evaluated by photocatalytic decoloration of methylene blue under visible-light irradiation(k[420 nm).The results showed that the as-prepared samples present high visible-light photocatalytic performances,which can be ascribed to the excellent crystallization,the enhancement of absorbance in the visible-light region,and the strong adsorption performance,and calcination treatment is helpful to further improve the visible-light photocatalytic performance of N-doped TiO2 nanocrystals with exposed{001}facets.展开更多
TiO_(2) nanosheets with dominant{001}facets,coupled with Cs_(2.5)H_(0.5)PW_(12)O_(40),were successfully synthesized by a one-step hydrothermal reaction.The photocatalytic activity of nanocatalysts was evaluated by the...TiO_(2) nanosheets with dominant{001}facets,coupled with Cs_(2.5)H_(0.5)PW_(12)O_(40),were successfully synthesized by a one-step hydrothermal reaction.The photocatalytic activity of nanocatalysts was evaluated by the degradation of Rhodamine B under UV light irradiation.The results showed that both the addition of Cs_(2.5)H_(0.5)PW_(12)O_(40) and the exposed{001}facets of TiO_(2) have a positive effect on the photocatalytic activity.The improved photoactivity of nanocomposites in comparison with that of TiO_(2) nanosheets could be attributed to the synergistic effect between Cs_(2.5)H_(0.5)PW_(12)O_(40) and TiO_(2) which facilitates the separation of photo-induced hole-electron pairs.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(20901040/B0111)the Innovation Foundation for Graduate Students of Jiangsu Province,China(CXLX11_0346)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions~~
基金financially supported by the National Natural Science Foundation of China(Nos. 51773226, 61701514)the Natural Science Foundation of Hunan Province(No. 2018JJ3603)
文摘The exposed crystal facet of TiO2 is a crucial factor influencing the gas sensing properties. TiO2 with high-energy{001}crystal facets that have higher surface energy and reactivity is expected to exhibit excellent gas-sensing properties. In this paper, TiO2 nanoplates with defective{001}facets were synthesized by chemical etching via one-step hydrothermal method. We carefully explored the gas-sensing performance of TiO2 nanoplates with defective and complete{001}facets towards acetone. The results show that the sensing response of TiO2 nanoplates with complete{001}facets is 70%higher than that of defective TiO2 nanoplates, which proves that the{001}facets plays a vital role in improving the gas sensing performance of TiO2. It is speculated that the poor gas sensitivity of defective TiO2 can be contributed to fewer adsorption sites and blocked electron transfer. This work presents a more direct evidence for explaining the important role of the complete{001}crystal facets in high sensitivity of TiO2 and also provides a new insight for preparing high sensitivity sensing materials.
基金This work was supported by the National Natural Science Foundation of China （Nos. 21473004 and 21673007） and the National Basic Research Program of China （No. 2013CB932601）.
文摘A facile, fluorine-free approach for synthesizing vertically aligned arrays of mesocrystaUine anatase TiO2 nanosheets with highly exposed {001} facets was developed through topotactic transformation. Unique mesocrystalline {001}-faceted TiO2 nanosheet arrays vertically aligned on conductive fluorine-doped tin oxide glass were realized through topotactic conversion from single-crystalline precursor nanosheet arrays based on lattice matching between the precursor and the anatase crystals. The morphology and microstructure of the {001}-faceted TiO2 nanosheets could be readily modulated by changing the reactant concentration and annealing temperature. Owing to enhanced dye adsorption, reduced charge recombination, and enhanced light scattering arising from the exposed {001} facets, in addition to the advantageous features of low-dimensional structure arrays （e.g., fast electron transport and efficient charge collection）, the obtained TiO2 nanosheet arrays exhibited superior performance when they were used as anodes for dye-sensitized solar cells （DSSCs）. Particularly, {001}-faceted TiO2 nanosheet arrays -15 μm long annealed at 500 ℃ showed a power conversion efficiency of 7.51%. Furthermore, a remarkable efficiency of 8.85% was achieved for a DSSC based on doubleqayered TiO2 nanosheet arrays -35 μm long, which were prepared by conversion from the precursor nanoarrays produced via secondary hydrothermal growth.
基金financially supported by the National Natural Science Foundation of China (Nos. 61434002, 51571135)National Science Foundation of United States (Nos. DMR-1104994, CBET-1510121)+1 种基金Shanxi Scholars Program (No. [2012]12), ‘‘One Hundred Talented People’’ of Shanxi ProvinceShanxi Province Foundations (Nos. [2012]10, [2013]9)
文摘Nitrogen （N） and phosphorus （P） co-doped anatase TiO2 nanosheets were realized by low-temperature self-doping N-TiO2 followed by high-temperature P doping with foreign precursor. It is found that P doping process can maintain good TiO2 nanosheets morphology with exposed {001} facets. Chemical state of dopants indicates that N and P atoms replace O on O sites in TiO2 lattice. Compared with pure TiO2 and N-doped TiO2, N-P codoped TiO2 nanosheets exhibits stronger optical absorption and higher degradation rate of dye molecules in visible light regime. The enhanced photocatalytic properties are attributed to two factors. On one hand, N-P co-doping can effectively reduce band gap of TiO2 from 3.20 to 2.48 eV, leading to an enhancement of the absorption in visible light regime. On the other hand, the presence of exposed {001} facets of TiO2 nanosheets can induce the effective sepa- ration of photogenerated electrons and holes in reaction.
文摘Anatase TiO2 with a variant percentage of exposed （001） facets was prepared under hydrothermal processes by adjusting the volume of HF, and the photocatalytic mechanism was studied from atomic-molecular scale by HRTEM and Raman spectroscopy. It was revealed that： 1） From HRTEM observations, the surface of original TiO2 with exposed （001） facets was clean without impurity, and the crystal lattice was clear and completed; however, when mixed with methylene blue （MB） solution, there were many 1 nm molecular absorbed at the surface of TiO2; after the photocatalytic experiment, MB molecules disappeared and the TiO2 lattice image became fuzzy. 2） The broken path of the MB chemical bond was obtained by Raman spectroscopy, i.e., after the irradiation of the light, the vibrational mode of C-N-C disappeared due to the chemical bond breakage, and the groups containing C-N bond and carbon rings were gradually decomposed. Accordingly, we propose that the driving force for breaking the chemical bond and the disappearance of groups is from the surface lattice distortion of TiO2 during photocatalyzation.
基金Project(21872174)supported by the National Natural Science Foundation of ChinaProjects(2017CX003,20180018050001)supported by the Innovation-Driven Plan in Central South University,China+3 种基金Project supported by State Key Laboratory of Powder Metallurgy in Central South University,ChinaProject(JCYJ20180307151313532)supported by Shenzhen Science and Technology Innovation Project,ChinaProject supported by the Thousand Youth Talents Plan of ChinaProject supported by the Hundred Youth Talents Program of Hunan,China
文摘Photocatalytic carbon dioxide reduction reaction(CO2RR)has been considered as one of most effective ways to solve the current energy crisis and environmental problems.However,the practical application of photocatalytic CO2RR is largely hindered by lock of efficient catalyst.Here,hierarchical titanium dioxide(TiO2)nanostructures with a highly active{001}surface were successfully synthesized by a facile approach from metal Ti powders.The obtained hierarchical TiO2 nanostructures were composed of TiO2 nanorods,which have a diameter about 5–10 nm and a length of several micrometers.It is found that these nanorods have exposed{001}facets.On the other hand,these hierarchical TiO2 nanostructures have a good light-harvesting efficiency with the help of TiO2 nanorods component and large specific surface area.Therefore,these hierarchical TiO2 nanostructures exhibit a much better activity for photocatalytic CO2 reduction than that of commercial TiO2(P25).This high activity can be attributed to the synergistic effects of active surface,efficient charge transfer along nanorods and good light harvesting in the nanorod-hierarchical nanostructures.
基金supported by the National Key R&D Program of China(2016YFC0204100)the Zhejiang Provincial "151" Talents Program+1 种基金the Program for Zhejiang Leading Team of S&T Innovation(2013TD07)the Changjiang Scholar Incentive Program(2009)~~
文摘A sample of sulfated anatase TiO2 with high‐energy(001)facets(TiO2‐001)was prepared by a simple one‐step hydrothermal route using SO42-as a morphology‐controlling agent.After doping ceria,Ce/TiO2‐001 was used as the catalyst for selective catalytic reduction(SCR)of NO with NH3.Compared with Ce/P25(Degussa P25 TiO2)and Ce/P25‐S(sulfated P25)catalysts,Ce/TiO2‐001 was more suitable for medium‐and high‐temperature SCR of NO due to the high surface area,sulfation,and the excellent properties of the active‐energy(001)facets.All of these facilitated the generation of abundant acidity,chemisorbed oxygen,and activated NOx‐adsorption species,which were the important factors for the SCR reaction.
基金supported by the Key Project of Science and Technology Plan of Fujian Province (2012Y0066)the Opening Project of State Key Laboratory of High Performance Ceramics and Superfine Microstructure (SKL201107SIC)+2 种基金the National High Technology Research and Development Program of China (2012AA062606)the International Science & Technology Cooperation Program of China (2011DFB91710)the Xiamen Distinguished Young Scholar Award (3502Z20126011)
文摘Anatase TiO2with exposed{001}facets has been deepgoingly studied for optimizing its photocatalytic activity.In this study,we synthesized N-doped TiO2 nanocrystals with exposed{001}facets by sol–gel method and solvothermal method,respectively.The physical and chemical properties of as-synthesized samples,such as morphology,crystal phase,surface elements composition,porous structure,specific surface area,and optical response,were characterized in detail.The photocatalytic performances of all samples were evaluated by photocatalytic decoloration of methylene blue under visible-light irradiation(k[420 nm).The results showed that the as-prepared samples present high visible-light photocatalytic performances,which can be ascribed to the excellent crystallization,the enhancement of absorbance in the visible-light region,and the strong adsorption performance,and calcination treatment is helpful to further improve the visible-light photocatalytic performance of N-doped TiO2 nanocrystals with exposed{001}facets.
基金This work was supported by the National Natural Science Foundation of China(Nos.21371035,21173050).
文摘TiO_(2) nanosheets with dominant{001}facets,coupled with Cs_(2.5)H_(0.5)PW_(12)O_(40),were successfully synthesized by a one-step hydrothermal reaction.The photocatalytic activity of nanocatalysts was evaluated by the degradation of Rhodamine B under UV light irradiation.The results showed that both the addition of Cs_(2.5)H_(0.5)PW_(12)O_(40) and the exposed{001}facets of TiO_(2) have a positive effect on the photocatalytic activity.The improved photoactivity of nanocomposites in comparison with that of TiO_(2) nanosheets could be attributed to the synergistic effect between Cs_(2.5)H_(0.5)PW_(12)O_(40) and TiO_(2) which facilitates the separation of photo-induced hole-electron pairs.
