Enhanced charge separation and conductivity of hematite enabled by versatile NiSe2 nanoparticles for improved photoelectrochemical water oxidation

The inherent drawbacks of severe charge recombination and poor conductivity of hematite (α-Fe 2 O 3 ) are still the obstacles for its applications. Herein, we report the integration of NiSe 2 nanoparticles on the surface of Fe 2 O 3 films for the photoelectrochemical (PEC) water oxidation. The resulting heterostructure photoanode exhibited significantly enhanced PEC performance with a current density enlarged by 50%. The investigations on mechanism reveals that a built-in electric field was formed to accelerate the charge transfer and separation, the charge carrier concentration was significantly enhanced by the formation of oxygen vacancies induced by NiSe 2 , the lifetime of photogenerated electrons and holes were substantially prolongated due to the suppression of recombination by the surface passivation and promoted surface kinetics for water oxidation by of Se-O species. This work brings inspiration to integrate multifunctional modifiers on photoelectrodes that allows for addressing several issues simultaneously and consequently improving the PEC performance for hydrogen production via water splitting.