Layered transition metal hydroxides show distinct advantages in separately co-catalyzing CO2reduction and H2O oxidation at the electron-accumulating and hole-accumulating sites of wrapped heterojunction photocat...Layered transition metal hydroxides show distinct advantages in separately co-catalyzing CO2reduction and H2O oxidation at the electron-accumulating and hole-accumulating sites of wrapped heterojunction photocatalysts,while concurrently preventing side reactions and photocorrosion on the semiconductor surface.Herein,Ni-Co bimetallic hydroxides with varying Ni/Co molar ratios(NixCo1-x(OH)2,x=1,0.75,0.5,0.25,and 0)were grown in situ on a model 2D/2D S-scheme heterojunction composed of Cu2O nanosheets and Fe2O3nanoplates to form a series of Cu2O/Fe2O3@NixCo1-x(OH)2(CF@NiCo)photocatalysts.The combined experimental and theoretical investigation demonstrates that incorporating an appropriate amount of Co into Ni(OH)2not only modulates the energy band structure of NixCo1-x(OH)2,balances the electron-and hole-trapping abilities of the bifunctional cocatalyst and maximizes the charge separation efficiency of the heterojunction,but also regulates the d-band center of NixCo1-x(OH)2,reinforcing the adsorption and activation of CO2and H2O on the cocatalyst surface and lowering the rate-limiting barriers in the CO2-to-CO and H2O-to-O2conversion.Benefiting from the Ni-Co synergy,the redox reactions proceed stoichiometrically.The optimized CF@Ni0.75Co0.25achieves CO and O2yields of 552.7 and 313.0μmol gcat-1h-1,respectively,11.3/9.9,1.6/1.7,and 4.5/5.9-fold higher than those of CF,CF@Ni,and CF@Co.This study offers valuable insights into the design of bifunctional noble-metal-free cocatalysts for high-performance artificial photosynthesis.展开更多
摘要Layered transition metal hydroxides show distinct advantages in separately co-catalyzing CO2reduction and H2O oxidation at the electron-accumulating and hole-accumulating sites of wrapped heterojunction photocatalysts,while concurrently preventing side reactions and photocorrosion on the semiconductor surface.Herein,Ni-Co bimetallic hydroxides with varying Ni/Co molar ratios(NixCo1-x(OH)2,x=1,0.75,0.5,0.25,and 0)were grown in situ on a model 2D/2D S-scheme heterojunction composed of Cu2O nanosheets and Fe2O3nanoplates to form a series of Cu2O/Fe2O3@NixCo1-x(OH)2(CF@NiCo)photocatalysts.The combined experimental and theoretical investigation demonstrates that incorporating an appropriate amount of Co into Ni(OH)2not only modulates the energy band structure of NixCo1-x(OH)2,balances the electron-and hole-trapping abilities of the bifunctional cocatalyst and maximizes the charge separation efficiency of the heterojunction,but also regulates the d-band center of NixCo1-x(OH)2,reinforcing the adsorption and activation of CO2and H2O on the cocatalyst surface and lowering the rate-limiting barriers in the CO2-to-CO and H2O-to-O2conversion.Benefiting from the Ni-Co synergy,the redox reactions proceed stoichiometrically.The optimized CF@Ni0.75Co0.25achieves CO and O2yields of 552.7 and 313.0μmol gcat-1h-1,respectively,11.3/9.9,1.6/1.7,and 4.5/5.9-fold higher than those of CF,CF@Ni,and CF@Co.This study offers valuable insights into the design of bifunctional noble-metal-free cocatalysts for high-performance artificial photosynthesis.