In situ synthesized In2O3/CuBi2O4 heterojunction photocathodes for efficient photoelectrochemical water splitting.

• In 2 O 3 /CuBi 2 O 4 heterojunction photocathodes are in situ formed. • The In 2 O 3 /CuBi 2 O 4 photocathode exhibits a significantly enhanced photocurrent. • Charge transfer in the In 2 O 3 /CuBi 2 O 4 heterojunction is much better than the pure CuBi 2 O 4. As a promising material for solar water splitting, p-type CuBi 2 O 4 semiconductor has attracted much attention due to its unique advantages. However, the photoelectrochemical (PEC) activity of the CuBi 2 O 4 is far from satisfactory due to its less efficient carrier transport. In this study, a doped method is used to prepare a layer of indium oxide on the surface of CuBi 2 O 4 , that is, a new In 2 O 3 /CuBi 2 O 4 heterojunction thin film is prepared. We compare the performance of pure CuBi 2 O 4 and In 2 O 3 /CuBi 2 O 4 through electrochemical testing and several physical characterizations. The final experimental results show that indium oxide can improve the PEC properties of CuBi 2 O 4 by reducing the recombination of electrons and holes and improve the charge transport. [ABSTRACT FROM AUTHOR]