Broad absorption spectra with efficient generation and separation of available charge carriers are indispensable requirements for promising semiconductor-based photocatalysts to achieve the ultimate goal of solar-to-f...Broad absorption spectra with efficient generation and separation of available charge carriers are indispensable requirements for promising semiconductor-based photocatalysts to achieve the ultimate goal of solar-to-fuel conversion.Here,Cu_(3-x)SnS_(4)(x=0-0.8)with copper vacancies have been prepared and fabricated via solvothermal process.The obtained copper vacancy materials have extended light absorption from ultraviolet to near-infrared-II region for its significant plasmonic effects.Time-resolved photoluminescence shows that the vacancies can simultaneously optimize charge carrier dynamics to boost the generation of long-lived active electrons for photocatalytic reduction.Density functional theory calculations and electrochemical characterizations further revealed that copper vacancies in Cu_(3-x)SnS_(4)tend to enhance hydrogen’s adsorption energy with an obvious decrease in its H_(2)evolution reaction(HER)overpotential.Furthermore,without any loadings,the H_(2)production rate was measured to be 9.5 mmol·h^(-1)·g^(-1).The apparent quantum yield was measured to be 27%for wavelengthλ>380 nm.The solar energy conversion efficiency was measured to be 6.5%under visible-near infrared(vis-NIR)(λ>420 nm).展开更多
Olefin epoxidation is an essential transformation and arouses great interest among the scientific community for the key role of epoxide in the chemical industry.Traditional methods suffer from harmful oxidants and req...Olefin epoxidation is an essential transformation and arouses great interest among the scientific community for the key role of epoxide in the chemical industry.Traditional methods suffer from harmful oxidants and require harsh operating conditions and complex separation processes.Electro-epoxidation through bromine redox reactions is an eco-friendly strategy.However,the lack of efficient electrodes always limits the selectivity of epoxidation and results in massive energy consumption.Herein,we found that GF-CoS_(2)/CoS heterostructures anchored on graphite felt(GF-CoS_(2)/CoS)can efficiently facilitate the generation of bromine redox species on the anode.The synergistic cooperation between the bromine redox species and oxygen redox species(generated on a graphite rod cathode)can establish a benign electro-epoxidation system for olefin substrates in an ambient environment.Under the optimized reaction conditions,the epoxidation of styrene can achieve a yield of 97% at 30 mA cm^(-2).Importantly,the applied voltage(4-5 V)is roughly half of the Pt-based electrode system(7.8-9.3 V),hence,saving half of the energy.We demonstrated that our proposed strategy could also be applied to other olefins.Because of the simple,sustainable,and economic advantages of the epoxidation process,we believe this strategy is highly desirable for technical applications.展开更多
基金The work is supported by the Science and Technology Commission of Shanghai Municipality(Nos.19JC1412600,20520741400,and 18230743400)the National Natural Science Foundation of China(Nos.21771124 and 21671134).
文摘Broad absorption spectra with efficient generation and separation of available charge carriers are indispensable requirements for promising semiconductor-based photocatalysts to achieve the ultimate goal of solar-to-fuel conversion.Here,Cu_(3-x)SnS_(4)(x=0-0.8)with copper vacancies have been prepared and fabricated via solvothermal process.The obtained copper vacancy materials have extended light absorption from ultraviolet to near-infrared-II region for its significant plasmonic effects.Time-resolved photoluminescence shows that the vacancies can simultaneously optimize charge carrier dynamics to boost the generation of long-lived active electrons for photocatalytic reduction.Density functional theory calculations and electrochemical characterizations further revealed that copper vacancies in Cu_(3-x)SnS_(4)tend to enhance hydrogen’s adsorption energy with an obvious decrease in its H_(2)evolution reaction(HER)overpotential.Furthermore,without any loadings,the H_(2)production rate was measured to be 9.5 mmol·h^(-1)·g^(-1).The apparent quantum yield was measured to be 27%for wavelengthλ>380 nm.The solar energy conversion efficiency was measured to be 6.5%under visible-near infrared(vis-NIR)(λ>420 nm).
基金supported by the Science and Technology Commission of Shanghai Municipality(20520741400,19JC1412600 and 18230743400)the National Natural Science Foundation of China(21771124 and 21901156).
文摘Olefin epoxidation is an essential transformation and arouses great interest among the scientific community for the key role of epoxide in the chemical industry.Traditional methods suffer from harmful oxidants and require harsh operating conditions and complex separation processes.Electro-epoxidation through bromine redox reactions is an eco-friendly strategy.However,the lack of efficient electrodes always limits the selectivity of epoxidation and results in massive energy consumption.Herein,we found that GF-CoS_(2)/CoS heterostructures anchored on graphite felt(GF-CoS_(2)/CoS)can efficiently facilitate the generation of bromine redox species on the anode.The synergistic cooperation between the bromine redox species and oxygen redox species(generated on a graphite rod cathode)can establish a benign electro-epoxidation system for olefin substrates in an ambient environment.Under the optimized reaction conditions,the epoxidation of styrene can achieve a yield of 97% at 30 mA cm^(-2).Importantly,the applied voltage(4-5 V)is roughly half of the Pt-based electrode system(7.8-9.3 V),hence,saving half of the energy.We demonstrated that our proposed strategy could also be applied to other olefins.Because of the simple,sustainable,and economic advantages of the epoxidation process,we believe this strategy is highly desirable for technical applications.
