Metal-organic frameworks(MOFs)have been developed as an ideal platform for exploration of the relationship between intrinsic structure and catalytic activity,but the limited catalytic activity and stability has hamper...Metal-organic frameworks(MOFs)have been developed as an ideal platform for exploration of the relationship between intrinsic structure and catalytic activity,but the limited catalytic activity and stability has hampered their practical use in water splitting.Herein,we develop a bond length adjustment strategy for optimizing naphthalene-based MOFs that synthesized by acid etching Co-naphthalenedicarboxylic acid-based MOFs(donated as AE-CoNDA)to serve as efficient catalyst for water splitting.AE-CoNDA exhibits a low overpotential of 260 mV to reach 10 mA cm^(−2)and a small Tafel slope of 62 mV dec^(−1)with excellent stability over 100 h.After integrated AE-CoNDA onto BiVO_(4),photocurrent density of 4.3 mA cm^(−2)is achieved at 1.23 V.Experimental investigations demonstrate that the stretched Co-O bond length was found to optimize the orbitals hybridization of Co 3d and O 2p,which accounts for the fast kinetics and high activity.Theoretical calculations reveal that the stretched Co-O bond length strengthens the adsorption of oxygen-contained intermediates at the Co active sites for highly efficient water splitting.展开更多
Developing stable and efficient nonprecious-metal-based oxygen evolution catalysts in the neutral electrolyte is a challenging but essential goal for various electrochemical systems.Particularly,cobalt-based spinels h...Developing stable and efficient nonprecious-metal-based oxygen evolution catalysts in the neutral electrolyte is a challenging but essential goal for various electrochemical systems.Particularly,cobalt-based spinels have drawn a considerable amount of attention but most of them operate in alkali solutions.However,the frequently studied Co-Fe spinel system never exhibits appreciable stability in nonbasic conditions,not to mention attract further investigation on its key structural motif and transition states for activity loss.Herein,we report exceptional stable Co-Fe spinel oxygen evolution catalysts(~30%Fe is optimal)in a neutral electrolyte,owing to its unique metal ion arrangements in the crystal lattice.The introduced iron content enters both the octahedral and tetrahedral sites of the spinel as Fe^(2+)and Fe^(3+)(with Co ions having mixed distribution as well).Combining density functional theory calculations,we find that the introduction of Fe to Co_(3)O_(4)lowers the covalency of metal-oxygen bonds and can help suppress the oxidation of Co^(2+/3+)and 0^(2-).It implies that the Co-Fe spinel will have minor surface reconstruction and less lattice oxygen loss during the oxygen evolution reaction process in comparison with Co_(3)O_(4)and hence show much better stability.These findings suggest that there is still much chance for the spinel structures,especially using reasonable sublattices engineering via multimetal doping to develop advanced oxygen evolution catalysts.展开更多
The retarded kinetics of oxygen evolution on electrodes is a bottleneck for electrochemical energy conversion and storage systems.NiFe-based electrocatalysts provide a cost-effective choice to confront this challenge....The retarded kinetics of oxygen evolution on electrodes is a bottleneck for electrochemical energy conversion and storage systems.NiFe-based electrocatalysts provide a cost-effective choice to confront this challenge.However,there is a lack of facile techniques for depositing compact catalytic films of high coverage and possessing a state-of-the-art performance,which is especially desired in photoelectrochemical(PEC)systems.Herein,we demonstrate a spray pyrolysis(SP)route to address this issue,featuring the kinetic selective preparation towards the desired catalytic-active material.Differing from reported SP protocols which only produce inactive oxides,this approach directly generates a unique composite film consisting of NiFe layered oxyhydroxides and amorphous oxides,exhibiting an overpotential as small as 255 mV(10 mA cm^(−2))and a turnover frequency of∼0.4 s^(−1)per metal atom.By using such a facile protocol,the surface rate-limiting issue of BiVO_(4)photoanodes can be effectively resolved,resulting in a charge injection efficiency of over 90%.Considering this deposition directly start from simple nitrates but only takes several seconds to complete,we believe it can be developed as a widely applicable and welcomed functionalization technique for diverse electrochemical devices.展开更多
Photoelectrocatalytic(PEC)materials for harvesting solar energy can be discovered from existing photocatalytic semiconductors.Nonetheless,mixed valence tin oxides,a group of widely reported visible light active photoc...Photoelectrocatalytic(PEC)materials for harvesting solar energy can be discovered from existing photocatalytic semiconductors.Nonetheless,mixed valence tin oxides,a group of widely reported visible light active photocatalysts,can hardly be developed into efficient PEC photoelectrodes.To overcome this difficulty by clarifying its origin,two typical mixed valence tin oxides,Sn^(2+):SnO_(2) microrods and porous Sn_(3)O_(4) particles were deliberately prepared as the models.Sn^(2+):SnO_(2) microrods of less porosity exhibited a photocurrent over ten times higher than Sn_(3)O_(4) particles.Photo-electrochemical impedance spectroscopy revealed this was due to their charge kinetics difference,specifically the internal transport/-transfer responding to the morphology.Moreover,hydroxyl residuals from synthesis were found to be very inhibitive for the PEC efficiency as well,which was in coherence with our TGA and Raman spectroscopic study.These finding experimentally proved the necessity of reconsidering the surface area,crystallinity,and defects when developing photocatalysts into efficient PEC structures.展开更多
Organic semiconductors are promising candidates as photoactive layers for photoelectrodes used in photoelectrochemical(PEC)cells due to their excellent light absorption and efficient charge transport properties with t...Organic semiconductors are promising candidates as photoactive layers for photoelectrodes used in photoelectrochemical(PEC)cells due to their excellent light absorption and efficient charge transport properties with the help of interfacial materials.However,the use of multilayers will make the charge transfer mechanism more complicated and decrease the PEC performance of the photoelectrode caused by the increased contact resistance.In this work,a PM6:Y6 bulk heterojunction(BHJ)-based photocathode is fabricated for efficient PEC hydrogen evolution reaction(HER)in an acidic aqueous solution.With RuO_(2)as an interfacial modification layer,the photocathode with a simple structure(fluorine-doped tin oxide(FTO)/PM6:Y6/RuO_(2))generates a maximum photocurrent density up to-15 m A/cm^(2)at 0 V vs.reference hydrogen electrode(RHE),outperforming all previously reported BHJ-based photocathodes in terms of PEC performance.The highest ratiometric power-saved efficiency of 3.7%is achieved at 0.4 V vs.RHE.展开更多
基金supported by the National Key Research and Development Program of China (2022YFB4002100)the development project of Zhejiang Province's "Jianbing" and "Lingyan" (2023C01226)+4 种基金the National Natural Science Foundation of China (22278364, U22A20432, 22238008, 22211530045, and 22178308)the Fundamental Research Funds for the Central Universities (226-2022-00044 and 226-2022-00055)the Science Foundation of Donghai Laboratory (DH-2022ZY0009)the Startup Foundation for Hundred-Talent Program of Zhejiang UniversityScientific Research Fund of Zhejiang Provincial Education Department.
文摘Metal-organic frameworks(MOFs)have been developed as an ideal platform for exploration of the relationship between intrinsic structure and catalytic activity,but the limited catalytic activity and stability has hampered their practical use in water splitting.Herein,we develop a bond length adjustment strategy for optimizing naphthalene-based MOFs that synthesized by acid etching Co-naphthalenedicarboxylic acid-based MOFs(donated as AE-CoNDA)to serve as efficient catalyst for water splitting.AE-CoNDA exhibits a low overpotential of 260 mV to reach 10 mA cm^(−2)and a small Tafel slope of 62 mV dec^(−1)with excellent stability over 100 h.After integrated AE-CoNDA onto BiVO_(4),photocurrent density of 4.3 mA cm^(−2)is achieved at 1.23 V.Experimental investigations demonstrate that the stretched Co-O bond length was found to optimize the orbitals hybridization of Co 3d and O 2p,which accounts for the fast kinetics and high activity.Theoretical calculations reveal that the stretched Co-O bond length strengthens the adsorption of oxygen-contained intermediates at the Co active sites for highly efficient water splitting.
基金the financial support by the National Natural Science Foundation of China(NSFC,grant nos.21905288 and 51904288)Zhejiang Provincial Natural Science Foundation(LZ21B030001)+3 种基金K.C.Wong Education Foundation(GJTD-2019-13)Ningbo major special projects of the Plan“Science and Technology Innovation 2025”(grant nos.2018B10056 and 2019B10046)Ningbo 3315 ProgramYongjiang Talent Introduction Program(no.2021A-115-G)
文摘Developing stable and efficient nonprecious-metal-based oxygen evolution catalysts in the neutral electrolyte is a challenging but essential goal for various electrochemical systems.Particularly,cobalt-based spinels have drawn a considerable amount of attention but most of them operate in alkali solutions.However,the frequently studied Co-Fe spinel system never exhibits appreciable stability in nonbasic conditions,not to mention attract further investigation on its key structural motif and transition states for activity loss.Herein,we report exceptional stable Co-Fe spinel oxygen evolution catalysts(~30%Fe is optimal)in a neutral electrolyte,owing to its unique metal ion arrangements in the crystal lattice.The introduced iron content enters both the octahedral and tetrahedral sites of the spinel as Fe^(2+)and Fe^(3+)(with Co ions having mixed distribution as well).Combining density functional theory calculations,we find that the introduction of Fe to Co_(3)O_(4)lowers the covalency of metal-oxygen bonds and can help suppress the oxidation of Co^(2+/3+)and 0^(2-).It implies that the Co-Fe spinel will have minor surface reconstruction and less lattice oxygen loss during the oxygen evolution reaction process in comparison with Co_(3)O_(4)and hence show much better stability.These findings suggest that there is still much chance for the spinel structures,especially using reasonable sublattices engineering via multimetal doping to develop advanced oxygen evolution catalysts.
基金financially supported by the National Natural Science Foundation of China(NSFC,21805298,21905288,51904288)the Zhejiang Provincial Natural Science Foundation(Z21B030017)+2 种基金the K.C.Wong Education Foundation(GJTD-201913)the Ningbo major special projects of the Plan‘‘Science and Technology Innovation 2025”(2018B10056,2019B10046)the Ningbo 3315 Program。
文摘The retarded kinetics of oxygen evolution on electrodes is a bottleneck for electrochemical energy conversion and storage systems.NiFe-based electrocatalysts provide a cost-effective choice to confront this challenge.However,there is a lack of facile techniques for depositing compact catalytic films of high coverage and possessing a state-of-the-art performance,which is especially desired in photoelectrochemical(PEC)systems.Herein,we demonstrate a spray pyrolysis(SP)route to address this issue,featuring the kinetic selective preparation towards the desired catalytic-active material.Differing from reported SP protocols which only produce inactive oxides,this approach directly generates a unique composite film consisting of NiFe layered oxyhydroxides and amorphous oxides,exhibiting an overpotential as small as 255 mV(10 mA cm^(−2))and a turnover frequency of∼0.4 s^(−1)per metal atom.By using such a facile protocol,the surface rate-limiting issue of BiVO_(4)photoanodes can be effectively resolved,resulting in a charge injection efficiency of over 90%.Considering this deposition directly start from simple nitrates but only takes several seconds to complete,we believe it can be developed as a widely applicable and welcomed functionalization technique for diverse electrochemical devices.
基金support by the National Natural Science Foundation of China(NSFC,Grant Nos.21805298,21905288,51904288)K.C.Wong Education Foundation(GJTD-2019-13)+1 种基金Ningbo major special projects of the Plan"Science and Technology Innovation 2025"(No.2018B10056,No.2019B10046)Ningbo 3315 Program。
文摘Photoelectrocatalytic(PEC)materials for harvesting solar energy can be discovered from existing photocatalytic semiconductors.Nonetheless,mixed valence tin oxides,a group of widely reported visible light active photocatalysts,can hardly be developed into efficient PEC photoelectrodes.To overcome this difficulty by clarifying its origin,two typical mixed valence tin oxides,Sn^(2+):SnO_(2) microrods and porous Sn_(3)O_(4) particles were deliberately prepared as the models.Sn^(2+):SnO_(2) microrods of less porosity exhibited a photocurrent over ten times higher than Sn_(3)O_(4) particles.Photo-electrochemical impedance spectroscopy revealed this was due to their charge kinetics difference,specifically the internal transport/-transfer responding to the morphology.Moreover,hydroxyl residuals from synthesis were found to be very inhibitive for the PEC efficiency as well,which was in coherence with our TGA and Raman spectroscopic study.These finding experimentally proved the necessity of reconsidering the surface area,crystallinity,and defects when developing photocatalysts into efficient PEC structures.
基金the financial support by the National Natural Science Foundation of China(NSFC,21905288,and 51904288)the Zhejiang Provincial Natural Science Foundation(No.LZ21B030017)+2 种基金K.C.Wong Education Foundation(No.GJTD-2019-13)Ningbo Major Special Projects of the Plan“Science and Technology Innovation 2025”(Nos.2018B10056,and 2019B10046)Ningbo 3315 Program,and Natural Science Foundation of Fujian Province(No.2021J011150)。
文摘Organic semiconductors are promising candidates as photoactive layers for photoelectrodes used in photoelectrochemical(PEC)cells due to their excellent light absorption and efficient charge transport properties with the help of interfacial materials.However,the use of multilayers will make the charge transfer mechanism more complicated and decrease the PEC performance of the photoelectrode caused by the increased contact resistance.In this work,a PM6:Y6 bulk heterojunction(BHJ)-based photocathode is fabricated for efficient PEC hydrogen evolution reaction(HER)in an acidic aqueous solution.With RuO_(2)as an interfacial modification layer,the photocathode with a simple structure(fluorine-doped tin oxide(FTO)/PM6:Y6/RuO_(2))generates a maximum photocurrent density up to-15 m A/cm^(2)at 0 V vs.reference hydrogen electrode(RHE),outperforming all previously reported BHJ-based photocathodes in terms of PEC performance.The highest ratiometric power-saved efficiency of 3.7%is achieved at 0.4 V vs.RHE.
