A molecular [Ru(bda)]-type(bda = 2,2’-bipyridine-6,6’-dicarboxylate) water oxidation catalyst with 4-vinylpyridine as the axial ligand(Complex 1) was immobilized or co-immobilized with 1-(trifluoromethyl)-4-vinylben...A molecular [Ru(bda)]-type(bda = 2,2’-bipyridine-6,6’-dicarboxylate) water oxidation catalyst with 4-vinylpyridine as the axial ligand(Complex 1) was immobilized or co-immobilized with 1-(trifluoromethyl)-4-vinylbenzene(3 F) or styrene(St) blocking units on the surface of glassy carbon(GC) electrodes by electrochemical polymerization, in order to prepare the corresponding poly-1@GC, poly-1+P3 F@GC, and poly-1+PSt@GC functional electrodes. Kinetic measurements of the electrode surface reaction revealed that [Ru(bda)] triggers the O–O bond formation via(1) the radical coupling interaction between the two metallo-oxyl radicals(I2 M) in the homo-coupling polymer(poly-1), and(2) the water nucleophilic attack(WNA) pathway in poly-1+P3 F and poly-1+PSt copolymers. The comparison of the three electrodes revealed that the second coordination sphere of the water oxidation catalysts plays vital roles in stabilizing their reaction intermediates, tuning the O–O bond formation pathways and improving the water oxidation reaction kinetics without changing the first coordination structures.展开更多
Herein,we report two approaches to the synthesis of heterometallic complexes(NH_(4)))_(2n)(H_(2)en)_(n){[Cu(en)_(2)][α-V_(2)Mo_(6)O_(26)]}·4nH_(2)O(1),(NH_(4))_(2){[Cu(dien)(H_(2)O)]_(2)[α-V_(2)Mo_(6)O_(26)]}&#...Herein,we report two approaches to the synthesis of heterometallic complexes(NH_(4)))_(2n)(H_(2)en)_(n){[Cu(en)_(2)][α-V_(2)Mo_(6)O_(26)]}·4nH_(2)O(1),(NH_(4))_(2){[Cu(dien)(H_(2)O)]_(2)[α-V_(2)Mo_(6)O_(26)]}·5H_(2)O(_(2))and(NH_(4))_(2){[Cu(dien)(H_(2)O)]_(2)[α-V_(2)Mo_(6)O_(26)]}·8H_(2)O(3)that have been employed in homogeneous photochemical oxidation of water to dioxygen.展开更多
Water oxidation, as a mandatory reaction of solar fuels conversion systems, requires the use of light absorbers with electronic properties that are well matched with those of the multi-electron catalyst in order to ac...Water oxidation, as a mandatory reaction of solar fuels conversion systems, requires the use of light absorbers with electronic properties that are well matched with those of the multi-electron catalyst in order to achieve high efficiency. Molecular light absorbers offer flexibility in fine tuning of orbital energetics,and metal oxide nanoparticles have emerged as robust oxygen evolving catalysts. Hence, these material choices offer a promising approach for the development of photocatalytic systems for water oxidation.However, efficient charge transfer coupling of molecular light absorbers and metal oxide nanoparticle catalysts has proven a challenge. Recent new approaches toward the efficient coupling of these components based on synthetic design improvements combined with direct spectroscopic observation and kinetic evaluation of charge transfer processes are discussed.展开更多
Homogeneous water oxidation catalysts play a crucial role in the efficient utilization of hydrogen energy.The exploration of cost-effective metal catalysts based on redox-active ligands represents a promising approach...Homogeneous water oxidation catalysts play a crucial role in the efficient utilization of hydrogen energy.The exploration of cost-effective metal catalysts based on redox-active ligands represents a promising approach in this field.Non-precious metal catalysts,especially copper-based complexes,have emerged as viable alternatives,addressing the challenges associated with precious metals.In this study,theoretical calculations were employed to deeply investigate the catalytic mechanism of electrochemical water oxidation reactions mediated by a copper complex with redox-active ligands.Our theoretical research reveals the reaction sequence of proton-coupled electron transfer(PCET)oxidation,where the ligand undergoes PCET oxidation first,followed by the coordination of water to the copper center.The calculated redox potentials are in close agreement with experimental values.We considered two possible active species,Cu^(II)-OH·and CuII^(-)O··,and the calculation results indicate that the reaction pathway of Cu-O··has a lower activation energy barrier.For the critical O-O bond formation process,the catalyst guides the reaction through a unique single-electron transfer-water nucleophilic attack(SET-WNA)mechanism.It is noteworthy that the copper center of all the intermediates remains at the+2 oxidation state,highlighting the redox inertness of copper.These findings provide theoretical guidance for optimizing copper-based water oxidation catalysts.展开更多
Magnesium and rare earth mixed oxides（Mg3 REOx（RE=La, Y. Ce）） were prepared and characterized by Xray diffraction（XRD）, N_2 adsorption-desorption, infrared spectra and microcalorimetry of CO_2. The results revea...Magnesium and rare earth mixed oxides（Mg3 REOx（RE=La, Y. Ce）） were prepared and characterized by Xray diffraction（XRD）, N_2 adsorption-desorption, infrared spectra and microcalorimetry of CO_2. The results reveal that the Mg_3 CeO_x catalyst is present in the form of Mg-Ce-O solid solution,while the Mg3 LaOx and Mg_3 YO_x catalysts are probably rare earth oxides dispersed on MgO surface. As a result, among the calcined Mg_3 REO_x catalysts, the Mg_3 CeO_x catalyst presents the highest rate constant for acetone aldolization, which is well correlated to its more homogeneous distribution of basic sites. In contrary, the Mg_3 YO_x catalyst exhibit the lowest catalytic activity for acetone aldolization. Upon hydration pre-treatment, the basic properties on the surface of the Mg_3 REO_x catalysts were changed markedly. The Mg_3 YO_x catalyst after hydration treatment shows the highest amount of basic sites on catalyst surface, and then exhibits the highest activity among the hydrated Mg_3 REO_x catalysts. These results make it possible to fine-tune basic sites for acetone aldolization.展开更多
Inspired by the Mn_(4)CaO_(5)cluster at the catalytic water oxidation center of natural enzymes,artificial multinuclear metal clusters have attracted significant attention as water oxidation catalysts due to their syn...Inspired by the Mn_(4)CaO_(5)cluster at the catalytic water oxidation center of natural enzymes,artificial multinuclear metal clusters have attracted significant attention as water oxidation catalysts due to their synergistic interactions among multiple metal atoms[1-8].Atomically precise metal cluster catalysts serve as model systems for uncovering the synergistic mechanisms of the oxygen evolution reaction(OER)[9-14].展开更多
文摘A molecular [Ru(bda)]-type(bda = 2,2’-bipyridine-6,6’-dicarboxylate) water oxidation catalyst with 4-vinylpyridine as the axial ligand(Complex 1) was immobilized or co-immobilized with 1-(trifluoromethyl)-4-vinylbenzene(3 F) or styrene(St) blocking units on the surface of glassy carbon(GC) electrodes by electrochemical polymerization, in order to prepare the corresponding poly-1@GC, poly-1+P3 F@GC, and poly-1+PSt@GC functional electrodes. Kinetic measurements of the electrode surface reaction revealed that [Ru(bda)] triggers the O–O bond formation via(1) the radical coupling interaction between the two metallo-oxyl radicals(I2 M) in the homo-coupling polymer(poly-1), and(2) the water nucleophilic attack(WNA) pathway in poly-1+P3 F and poly-1+PSt copolymers. The comparison of the three electrodes revealed that the second coordination sphere of the water oxidation catalysts plays vital roles in stabilizing their reaction intermediates, tuning the O–O bond formation pathways and improving the water oxidation reaction kinetics without changing the first coordination structures.
基金supported by the Swedish Institute(Grant No.23913/2017)the Ministry of Education and Science of Ukraine.
文摘Herein,we report two approaches to the synthesis of heterometallic complexes(NH_(4)))_(2n)(H_(2)en)_(n){[Cu(en)_(2)][α-V_(2)Mo_(6)O_(26)]}·4nH_(2)O(1),(NH_(4))_(2){[Cu(dien)(H_(2)O)]_(2)[α-V_(2)Mo_(6)O_(26)]}·5H_(2)O(_(2))and(NH_(4))_(2){[Cu(dien)(H_(2)O)]_(2)[α-V_(2)Mo_(6)O_(26)]}·8H_(2)O(3)that have been employed in homogeneous photochemical oxidation of water to dioxygen.
基金supported by the Director,Office of Science,Office of Basic Energy Sciences,Division of Chemical,Geological and Biosciences of the U.S.Department of Energy under Contract No.DE-AC02-05CH11231
文摘Water oxidation, as a mandatory reaction of solar fuels conversion systems, requires the use of light absorbers with electronic properties that are well matched with those of the multi-electron catalyst in order to achieve high efficiency. Molecular light absorbers offer flexibility in fine tuning of orbital energetics,and metal oxide nanoparticles have emerged as robust oxygen evolving catalysts. Hence, these material choices offer a promising approach for the development of photocatalytic systems for water oxidation.However, efficient charge transfer coupling of molecular light absorbers and metal oxide nanoparticle catalysts has proven a challenge. Recent new approaches toward the efficient coupling of these components based on synthetic design improvements combined with direct spectroscopic observation and kinetic evaluation of charge transfer processes are discussed.
基金supported by the NSFC(22263004)the National Natural Science Foundation of Guangxi Province(AD22035152).
文摘Homogeneous water oxidation catalysts play a crucial role in the efficient utilization of hydrogen energy.The exploration of cost-effective metal catalysts based on redox-active ligands represents a promising approach in this field.Non-precious metal catalysts,especially copper-based complexes,have emerged as viable alternatives,addressing the challenges associated with precious metals.In this study,theoretical calculations were employed to deeply investigate the catalytic mechanism of electrochemical water oxidation reactions mediated by a copper complex with redox-active ligands.Our theoretical research reveals the reaction sequence of proton-coupled electron transfer(PCET)oxidation,where the ligand undergoes PCET oxidation first,followed by the coordination of water to the copper center.The calculated redox potentials are in close agreement with experimental values.We considered two possible active species,Cu^(II)-OH·and CuII^(-)O··,and the calculation results indicate that the reaction pathway of Cu-O··has a lower activation energy barrier.For the critical O-O bond formation process,the catalyst guides the reaction through a unique single-electron transfer-water nucleophilic attack(SET-WNA)mechanism.It is noteworthy that the copper center of all the intermediates remains at the+2 oxidation state,highlighting the redox inertness of copper.These findings provide theoretical guidance for optimizing copper-based water oxidation catalysts.
基金Project supported by National Basic Research Program of China(2010CB732300)111 Project(B08021)China Scholarship Council for the Joint-Training Scholarship Program with Institut de Recherches sur la Catalyse et l'Environnement de Lyon(IRCELYON)and Universite Claude Bernard Lyon 1(UCBL1)
文摘Magnesium and rare earth mixed oxides（Mg3 REOx（RE=La, Y. Ce）） were prepared and characterized by Xray diffraction（XRD）, N_2 adsorption-desorption, infrared spectra and microcalorimetry of CO_2. The results reveal that the Mg_3 CeO_x catalyst is present in the form of Mg-Ce-O solid solution,while the Mg3 LaOx and Mg_3 YO_x catalysts are probably rare earth oxides dispersed on MgO surface. As a result, among the calcined Mg_3 REO_x catalysts, the Mg_3 CeO_x catalyst presents the highest rate constant for acetone aldolization, which is well correlated to its more homogeneous distribution of basic sites. In contrary, the Mg_3 YO_x catalyst exhibit the lowest catalytic activity for acetone aldolization. Upon hydration pre-treatment, the basic properties on the surface of the Mg_3 REO_x catalysts were changed markedly. The Mg_3 YO_x catalyst after hydration treatment shows the highest amount of basic sites on catalyst surface, and then exhibits the highest activity among the hydrated Mg_3 REO_x catalysts. These results make it possible to fine-tune basic sites for acetone aldolization.
基金supported by the National Natural Science Foundation of China(92461035,92161104,92161203,92361301)Fujian Province(2024J01313)。
文摘Inspired by the Mn_(4)CaO_(5)cluster at the catalytic water oxidation center of natural enzymes,artificial multinuclear metal clusters have attracted significant attention as water oxidation catalysts due to their synergistic interactions among multiple metal atoms[1-8].Atomically precise metal cluster catalysts serve as model systems for uncovering the synergistic mechanisms of the oxygen evolution reaction(OER)[9-14].
