The effect of the Al2O3 structure on the performance of Pt/Ga/Al2O3 catalysts is investigated for the direct dehydrogenation of propane. The study unveils that the structure of Al3+determines the bulk structure of cat...The effect of the Al2O3 structure on the performance of Pt/Ga/Al2O3 catalysts is investigated for the direct dehydrogenation of propane. The study unveils that the structure of Al3+determines the bulk structure of catalysts, particularly a high content of coordinatively unsaturated Al3+sites(penta-coordinated Al3+,denoted as Al3+penta) could lead to a remarkably improved dehydrogenation activity of the catalyst. The bulk characterization reveals that the sufficient amount of Al3+pentain Al2O3 benefit the dispersion of Pt and Ga2O3 on the Al2O3 support. At the same time, TPR results reveal that the presence of Pt facilitates the reduction of Ga2O3, likely due to the hydrogen spillover between the well dispersed Pt and Ga2O3,which consequently enhances the synergistic function between Pt and Ga2O3 in the dehydrogenation of propane. Recyclability tests demonstrate that the dehydrogenation activity stabilizes after three cycles over the Pt/Ga/Al2O3 catalyst.展开更多
Zeolites with ordered porous structure of molecular size are widely employed as commercial adsorbents and catalysts.On the other hand,the zeolite matrix is regarded as an ideal scaffold for hosting coordinatively unsa...Zeolites with ordered porous structure of molecular size are widely employed as commercial adsorbents and catalysts.On the other hand,the zeolite matrix is regarded as an ideal scaffold for hosting coordinatively unsaturated sites.Remarkable achievements have been made dealing with the construction,characterization and catalytic applications of coordinatively unsaturated sites in zeolite matrix.Herein,a literature overview of recent progresses on this important topic is presented from the specific view of coordination chemistry.Different strategies to construction coordinatively unsaturated sites in zeolite matrix,in zeolite framework or extraframework positions,are first introduced and their characteristics are compared.Then,spectroscopic techniques to determine the existing states of cation sites and their transformations in zeolite matrix are discussed.In the last section,the catalytic applications of coordinatively unsaturated sites in zeolite matrix for various important chemical transformations are summarized.展开更多
Defect sites on oxide semiconductors play a crucial role in promoting photocatalytiperformance and mod-ulating the bandgap structure of photocatalysts.However,the role of interfacial coordinatively unsatu-rated defect...Defect sites on oxide semiconductors play a crucial role in promoting photocatalytiperformance and mod-ulating the bandgap structure of photocatalysts.However,the role of interfacial coordinatively unsatu-rated defect sites between metal and oxide in photocatalysis is still under debate.So,we designed an experiment to probe the role of interfacial coordinatively unsaturated defect sites.In this work,a se-ries of Ti/TiO_(2) photocatalysts with varying concentrations of interfacial Ti^(3+)sites were prepared through an epitaxial growth method under hydrothermal conditions.Through experimental and computational investigations,the roles of interfacial defect sites were discussed in detail.On the one hand,the inter-facial coordinatively unsaturated Ti^(3+)sites could act as visible-light-responsive sites in photocatalytic reactions due to the overlap and hybridization of multiple electronic orbitals.On the other hand,the Ti/TiO_(2) interface exhibited a certain degree of metallic character near the Fermi level because of the par-tial delocalization and redistribution of electrons,facilitating the charge migration and separation across the metal-oxide interface.Consequently,the obtained Ti/TiO_(2) catalysts showed notably enhanced charge transfer efficiency and visible light photocatalytic activity compared to their pristine counterparts.This work may provide a new perspective to interfacial defect engineering in classic metal/oxide heterojunc-tion photocatalysts and figure a more precise direction to synthesize higher effective photocatalysts for environmental governance.展开更多
Defective bulk catalysts based on TiO_(2) have superior catalytic performance for propane dehydrogenation(PDH).The oxygen vacancy concentration and the number of active sites on the catalyst surface can be effectively...Defective bulk catalysts based on TiO_(2) have superior catalytic performance for propane dehydrogenation(PDH).The oxygen vacancy concentration and the number of active sites on the catalyst surface can be effectively tuned by doping metal in TiO_(2).Herein,yttrium(Y)-doped titanium dioxide(nY/TiO_(x))catalysts were in-situ synthesized via the coprecipitation method to study the effect of rare earth metal Y doping on the structure of TiO_(2) and the catalytic performance for PDH.Experimental results demonstrate that Ydoped TiO_(2) exhibits higher catalytic activity,propylene selectivity and stability than bare TiO_(2).Full characterizations with X-ray diffraction(XRD),high-resolution transmission electron microscope(HRTEM),X-ray photoelectron spectroscopy(XPS),infrared spectroscopy of pyridine adsorption(Py-IR),temperature-programmed desorption of ammonia(NH_(3)-TPD),H_(2) temperature-programmed reduction(H_2-TPR),and Raman techniques on these catalysts reveal that Y^(3+)can enter TiO_(2) lattice,and the lattice stability of the catalyst can be enhanced by replacing Ti^(4+)to form Y-O-Ti structure.Meanwhile,the introduction of an appropriate amount of Y can obviously promote the PDH reaction by adjusting the acidity of the catalyst,improving the release capacity of TiO_(2) lattice oxygen and increasing the formation of active centers.Nevertheless,excessive Y doping will lead to pore clogging,and the exposure of active sites will be reduced,resulting in the degradation of catalytic performance.展开更多
Classifying the types and measurin g sustainable development are important contents of theoretical studie s on sustainable development.Scient ifically reflecting the characteristics of sustainable development an d fav...Classifying the types and measurin g sustainable development are important contents of theoretical studie s on sustainable development.Scient ifically reflecting the characteristics of sustainable development an d favorably classify-ing the types of sustainable develop ment are the basis and objective of me asuring sustainable development.B y using the methods of coordinatively analyzin g man-land relationship and economi c analysis,especially by combining with constant elasticity of substitution(CES)production function,this paper advances average sustainable gross dom estic production(ASGDP),inquires into the mutually coordin ative and interdependent relationship between humane capital and natur al capital in the process of sustainabl e development.It also sets up an index system of measuring sustainable development and a type systemof sustainable deve lopment.then according to this index system,if firstly classifies the s ustainable develop-ment,moderate sustainable develop ment,and strong sustainable develo pment,and it also discuss them theoretical signifi-cance.Secondly,it probes into the minimum cost,structure optimizatio n and sustainable development.At la st,it dis-cuss the type classification of sustainable development on development sequence,and points out theoretically the amount of transitions among 8basic regional sustainable development types is 56.in the process of productive expan sion this transi-tion type embodies the input increase of humane capital is greatly larger than that of natural capital.On the c ontrary,econo-mized humane capital transition is a result of progressively decreasing marginal rate of technical substitu tion of humane capital to natural capital.展开更多
Zeolitic-imidazole frameworks(ZIFs)derivations have widely emerged as an efficient air cathode of zinc-air batteries(ZABs)due to excellent bifunctional oxygen electrocatalysis performance.However,they are not stable e...Zeolitic-imidazole frameworks(ZIFs)derivations have widely emerged as an efficient air cathode of zinc-air batteries(ZABs)due to excellent bifunctional oxygen electrocatalysis performance.However,they are not stable enough for long-term operation of rechargeable ZABs because of weak association with current collector,especially under bending conditions for flexible ZAB devices.Here,we show that by purposely designing coordinatively unsaturated ZIFs via a facile morphology regulation,which can be chemically linked on acid-treated carbon cloth,a stable Co-N-C air cathode is therefore derived where Co nanoparticles(NPs)are uniformly confined within the Co-N-C matrix on carbon cloth(Co/Co-N-C/CC).Specifically,when without being stabilized from carbon cloth,the pyrolysis of ZIFs with different unsaturated coordination levels has a negligible impact on the bifunctional oxygen-catalyzed performance.The optimal Co/Co-N-C/CC catalyst assembled ZAB possesses a large open circuit voltage of 1.415 V and a high peak power density of 163 mW·cm^(−2) as well as excellent cycling durability upon 630 discharge–charge cycles with 61%voltage efficiency remained,largely exceeding those of a benchmark Pt/C-IrO_(2) catalyst assembled ZAB.The synergy between Co NPs and active Co-N-C sites via electronic interaction induces the outstanding bifunctional oxygen-catalyzed activity and cathode performance.The present work highlights the importance of unsaturated coordination structures in ZIFs precursors for the performance of derived nanostructures in integrated electrodes.展开更多
A H_(2)O_(2)etching strategy was adopted to introduce coordinatively unsaturated sites(CUS)on MoS_(2)-based catalysts for dibenzothiophene(DBT)hydrodesulfurization(HDS).The CUS concentrations on MoS_(2) slabs were fin...A H_(2)O_(2)etching strategy was adopted to introduce coordinatively unsaturated sites(CUS)on MoS_(2)-based catalysts for dibenzothiophene(DBT)hydrodesulfurization(HDS).The CUS concentrations on MoS_(2) slabs were finely regulated by changing the concentrations of H_(2)O_(2)solution.With the increasing H_(2)O_(2)concentrations(0.1–0.3 mol/L),The CUS concentrations on MoS_(2) slabs increased gradually.However,the high-concentration H_(2)O_(2)etching(0.5 mol/L)increased the MoOxSy and MoO_(3) contents on MoS_(2) slabs compared to etching with the H_(2)O_(2)concentration of 0.3 mol/L,which led to the less CUS concentration in the sulfided Mo–H-0.5 catalyst than in the sulfided Mo–H-0.3 catalyst.A microstructure-activity correlation indicated that the CUS introduced by H_(2)O_(2)etching on MoS_(2) slabs significantly enhanced DBT HDS.Different Co loadings were further introduced into Mo–H-0.3,which had the most CUS concentration,and the corresponding 0.2-CoMo catalyst with the highest CoMoS content(3.853 wt%)exhibited the highest reaction rate constant of 6.95×10^(−6)mol g^(−1)s^(−1)among these CoMo catalysts.展开更多
The low intrinsic activity of Fenton catalytic site and high demand for light-energy input inhibit the organic-pollution control efficiency of photo-Fenton process.Here,through structural design with density functiona...The low intrinsic activity of Fenton catalytic site and high demand for light-energy input inhibit the organic-pollution control efficiency of photo-Fenton process.Here,through structural design with density functional theory(DFT)calculations,Ce is predicted to enable the construction of coordinatively unsaturated metal centers(CUCs)in Prussian blue analogue(PBA),which can strongly adsorb H_(2)O_(2)and donate sufficient electrons for directly splitting the O-O bond to produceOH.Using a substitution-co-assembly strategy,binary Ce-Fe PBA is then prepared,which rapidly degrades sulfamethoxazole with the pseudo-first-order kinetic rate constant exceeding reported values by 1-2 orders of magnitude.Meanwhile,the photogenerated electrons reduce Fe(Ⅲ)and Ce(Ⅳ)to promote the metal valence cycle in CUCs and make sulfamethoxazole degradation efficiency only lose 6.04%in 5 runs.Overall,by introducing rare earth metals into transition metal-organic frameworks,this work guides the whole process for highly active CUCs from design and construction to mechanism exploration with DFT calculations,enabling ultrafast and stable photo-Fenton catalysis.展开更多
Some Schiff-base cobalt(Ⅱ)chelates like ethylenebis[(2-hydroxy-3- methoxy-5-methylphenyl)methylideneiminato]Cobalt(Ⅱ)were coordioatively anchored onto poly(4-vinylpyridine-co-styrene)in diglyme solution and the diox...Some Schiff-base cobalt(Ⅱ)chelates like ethylenebis[(2-hydroxy-3- methoxy-5-methylphenyl)methylideneiminato]Cobalt(Ⅱ)were coordioatively anchored onto poly(4-vinylpyridine-co-styrene)in diglyme solution and the dioxygen-affinity of the resulting polymeric complexes were measured in situ.展开更多
基金the National Natural Science Foundation of China(No.21676195)the China Postdoctoral Science Foundation(2016M601347)。
文摘The effect of the Al2O3 structure on the performance of Pt/Ga/Al2O3 catalysts is investigated for the direct dehydrogenation of propane. The study unveils that the structure of Al3+determines the bulk structure of catalysts, particularly a high content of coordinatively unsaturated Al3+sites(penta-coordinated Al3+,denoted as Al3+penta) could lead to a remarkably improved dehydrogenation activity of the catalyst. The bulk characterization reveals that the sufficient amount of Al3+pentain Al2O3 benefit the dispersion of Pt and Ga2O3 on the Al2O3 support. At the same time, TPR results reveal that the presence of Pt facilitates the reduction of Ga2O3, likely due to the hydrogen spillover between the well dispersed Pt and Ga2O3,which consequently enhances the synergistic function between Pt and Ga2O3 in the dehydrogenation of propane. Recyclability tests demonstrate that the dehydrogenation activity stabilizes after three cycles over the Pt/Ga/Al2O3 catalyst.
基金supported by the National Natural Science Fundation of China(21722303,21421001)the Municipal Natural Science Fund of Tianjin(18JCJQJC47400,18JCZDJC37400)111 Project(B12015,B18030)~~
文摘Zeolites with ordered porous structure of molecular size are widely employed as commercial adsorbents and catalysts.On the other hand,the zeolite matrix is regarded as an ideal scaffold for hosting coordinatively unsaturated sites.Remarkable achievements have been made dealing with the construction,characterization and catalytic applications of coordinatively unsaturated sites in zeolite matrix.Herein,a literature overview of recent progresses on this important topic is presented from the specific view of coordination chemistry.Different strategies to construction coordinatively unsaturated sites in zeolite matrix,in zeolite framework or extraframework positions,are first introduced and their characteristics are compared.Then,spectroscopic techniques to determine the existing states of cation sites and their transformations in zeolite matrix are discussed.In the last section,the catalytic applications of coordinatively unsaturated sites in zeolite matrix for various important chemical transformations are summarized.
基金financialy supported by the National Key Research and Development Plan of China (No.2016YFC0209305)the Science and Technology Plans of Tianjin (No.18PTZWHZ00180)+1 种基金the Major National Science and Technology Projects (No.2017ZX07106001)the Tianjin Development Program for Innovation and Entrepreneurship。
文摘Defect sites on oxide semiconductors play a crucial role in promoting photocatalytiperformance and mod-ulating the bandgap structure of photocatalysts.However,the role of interfacial coordinatively unsatu-rated defect sites between metal and oxide in photocatalysis is still under debate.So,we designed an experiment to probe the role of interfacial coordinatively unsaturated defect sites.In this work,a se-ries of Ti/TiO_(2) photocatalysts with varying concentrations of interfacial Ti^(3+)sites were prepared through an epitaxial growth method under hydrothermal conditions.Through experimental and computational investigations,the roles of interfacial defect sites were discussed in detail.On the one hand,the inter-facial coordinatively unsaturated Ti^(3+)sites could act as visible-light-responsive sites in photocatalytic reactions due to the overlap and hybridization of multiple electronic orbitals.On the other hand,the Ti/TiO_(2) interface exhibited a certain degree of metallic character near the Fermi level because of the par-tial delocalization and redistribution of electrons,facilitating the charge migration and separation across the metal-oxide interface.Consequently,the obtained Ti/TiO_(2) catalysts showed notably enhanced charge transfer efficiency and visible light photocatalytic activity compared to their pristine counterparts.This work may provide a new perspective to interfacial defect engineering in classic metal/oxide heterojunc-tion photocatalysts and figure a more precise direction to synthesize higher effective photocatalysts for environmental governance.
基金Project supported by the National Natural Science Foundation of China(22172192,92145301)National Key Research and Development Program(2021YFB3500603)。
文摘Defective bulk catalysts based on TiO_(2) have superior catalytic performance for propane dehydrogenation(PDH).The oxygen vacancy concentration and the number of active sites on the catalyst surface can be effectively tuned by doping metal in TiO_(2).Herein,yttrium(Y)-doped titanium dioxide(nY/TiO_(x))catalysts were in-situ synthesized via the coprecipitation method to study the effect of rare earth metal Y doping on the structure of TiO_(2) and the catalytic performance for PDH.Experimental results demonstrate that Ydoped TiO_(2) exhibits higher catalytic activity,propylene selectivity and stability than bare TiO_(2).Full characterizations with X-ray diffraction(XRD),high-resolution transmission electron microscope(HRTEM),X-ray photoelectron spectroscopy(XPS),infrared spectroscopy of pyridine adsorption(Py-IR),temperature-programmed desorption of ammonia(NH_(3)-TPD),H_(2) temperature-programmed reduction(H_2-TPR),and Raman techniques on these catalysts reveal that Y^(3+)can enter TiO_(2) lattice,and the lattice stability of the catalyst can be enhanced by replacing Ti^(4+)to form Y-O-Ti structure.Meanwhile,the introduction of an appropriate amount of Y can obviously promote the PDH reaction by adjusting the acidity of the catalyst,improving the release capacity of TiO_(2) lattice oxygen and increasing the formation of active centers.Nevertheless,excessive Y doping will lead to pore clogging,and the exposure of active sites will be reduced,resulting in the degradation of catalytic performance.
文摘Classifying the types and measurin g sustainable development are important contents of theoretical studie s on sustainable development.Scient ifically reflecting the characteristics of sustainable development an d favorably classify-ing the types of sustainable develop ment are the basis and objective of me asuring sustainable development.B y using the methods of coordinatively analyzin g man-land relationship and economi c analysis,especially by combining with constant elasticity of substitution(CES)production function,this paper advances average sustainable gross dom estic production(ASGDP),inquires into the mutually coordin ative and interdependent relationship between humane capital and natur al capital in the process of sustainabl e development.It also sets up an index system of measuring sustainable development and a type systemof sustainable deve lopment.then according to this index system,if firstly classifies the s ustainable develop-ment,moderate sustainable develop ment,and strong sustainable develo pment,and it also discuss them theoretical signifi-cance.Secondly,it probes into the minimum cost,structure optimizatio n and sustainable development.At la st,it dis-cuss the type classification of sustainable development on development sequence,and points out theoretically the amount of transitions among 8basic regional sustainable development types is 56.in the process of productive expan sion this transi-tion type embodies the input increase of humane capital is greatly larger than that of natural capital.On the c ontrary,econo-mized humane capital transition is a result of progressively decreasing marginal rate of technical substitu tion of humane capital to natural capital.
基金supported by the Fundamental Research Funds for the Central Universities(No.40120631)Natural Science Foundation of Hubei Province(No.20211j0188).
文摘Zeolitic-imidazole frameworks(ZIFs)derivations have widely emerged as an efficient air cathode of zinc-air batteries(ZABs)due to excellent bifunctional oxygen electrocatalysis performance.However,they are not stable enough for long-term operation of rechargeable ZABs because of weak association with current collector,especially under bending conditions for flexible ZAB devices.Here,we show that by purposely designing coordinatively unsaturated ZIFs via a facile morphology regulation,which can be chemically linked on acid-treated carbon cloth,a stable Co-N-C air cathode is therefore derived where Co nanoparticles(NPs)are uniformly confined within the Co-N-C matrix on carbon cloth(Co/Co-N-C/CC).Specifically,when without being stabilized from carbon cloth,the pyrolysis of ZIFs with different unsaturated coordination levels has a negligible impact on the bifunctional oxygen-catalyzed performance.The optimal Co/Co-N-C/CC catalyst assembled ZAB possesses a large open circuit voltage of 1.415 V and a high peak power density of 163 mW·cm^(−2) as well as excellent cycling durability upon 630 discharge–charge cycles with 61%voltage efficiency remained,largely exceeding those of a benchmark Pt/C-IrO_(2) catalyst assembled ZAB.The synergy between Co NPs and active Co-N-C sites via electronic interaction induces the outstanding bifunctional oxygen-catalyzed activity and cathode performance.The present work highlights the importance of unsaturated coordination structures in ZIFs precursors for the performance of derived nanostructures in integrated electrodes.
基金support of the National Natural Science Foundation of China(Grant Nos.21978323 and 22108145).
文摘A H_(2)O_(2)etching strategy was adopted to introduce coordinatively unsaturated sites(CUS)on MoS_(2)-based catalysts for dibenzothiophene(DBT)hydrodesulfurization(HDS).The CUS concentrations on MoS_(2) slabs were finely regulated by changing the concentrations of H_(2)O_(2)solution.With the increasing H_(2)O_(2)concentrations(0.1–0.3 mol/L),The CUS concentrations on MoS_(2) slabs increased gradually.However,the high-concentration H_(2)O_(2)etching(0.5 mol/L)increased the MoOxSy and MoO_(3) contents on MoS_(2) slabs compared to etching with the H_(2)O_(2)concentration of 0.3 mol/L,which led to the less CUS concentration in the sulfided Mo–H-0.5 catalyst than in the sulfided Mo–H-0.3 catalyst.A microstructure-activity correlation indicated that the CUS introduced by H_(2)O_(2)etching on MoS_(2) slabs significantly enhanced DBT HDS.Different Co loadings were further introduced into Mo–H-0.3,which had the most CUS concentration,and the corresponding 0.2-CoMo catalyst with the highest CoMoS content(3.853 wt%)exhibited the highest reaction rate constant of 6.95×10^(−6)mol g^(−1)s^(−1)among these CoMo catalysts.
基金supported by the National Natural Science Foundation of China(No.22072064,51522805,51908273,and 22176086)the State Key Laboratory of Pollution Control and Resource Reuse(PCRR-ZZ-202106)Start-Up Funds for Jiangsu Distinguished Professor.
文摘The low intrinsic activity of Fenton catalytic site and high demand for light-energy input inhibit the organic-pollution control efficiency of photo-Fenton process.Here,through structural design with density functional theory(DFT)calculations,Ce is predicted to enable the construction of coordinatively unsaturated metal centers(CUCs)in Prussian blue analogue(PBA),which can strongly adsorb H_(2)O_(2)and donate sufficient electrons for directly splitting the O-O bond to produceOH.Using a substitution-co-assembly strategy,binary Ce-Fe PBA is then prepared,which rapidly degrades sulfamethoxazole with the pseudo-first-order kinetic rate constant exceeding reported values by 1-2 orders of magnitude.Meanwhile,the photogenerated electrons reduce Fe(Ⅲ)and Ce(Ⅳ)to promote the metal valence cycle in CUCs and make sulfamethoxazole degradation efficiency only lose 6.04%in 5 runs.Overall,by introducing rare earth metals into transition metal-organic frameworks,this work guides the whole process for highly active CUCs from design and construction to mechanism exploration with DFT calculations,enabling ultrafast and stable photo-Fenton catalysis.
文摘Some Schiff-base cobalt(Ⅱ)chelates like ethylenebis[(2-hydroxy-3- methoxy-5-methylphenyl)methylideneiminato]Cobalt(Ⅱ)were coordioatively anchored onto poly(4-vinylpyridine-co-styrene)in diglyme solution and the dioxygen-affinity of the resulting polymeric complexes were measured in situ.
基金supported by the National Natural Science Foundation of China(21978325 and 22122807)Outstanding Youth Fund of the National Natural Science Foundation of China(22122807)+1 种基金Outstanding Youth Fund of Shandong Provincial Natural Science Foundation(ZR2020YQ17)Natural Science Foundation of Shandong Province(ZR2020KB006)。
