Building directional charge transport channel and injecting hot electron in a ternary CeO2-based nanosheet arrays photoanode for efficient photoelectrochemical hydrogen evolution

Modulating band alignment for efficient carrier transport and manipulating charge carrier injection for improved carrier concentration is essential for semiconductor photoanode to achieve highly efficient photoelectrochemical (PEC) water splitting performance. Herein, CdSe and Au are exploited to sensitize CeO2 nanosheet arrays (NSAs) photoanode via electrochemical deposition and magnetron sputtering, successively, to build directional interfacial charge transfer channel and inject hot electrons respectively for efficient PEC hydrogen evolution. The constructed CeO2/CdSe/Au NSAs photoanode yields a significant hydrogen production rate of 58.4 μmol·cm−2·h−1 at 0 V vs Ag/AgCl, 7.5 times higher than that of CeO2 NSAs photoanode. Spectral measurements evidence that directional interfacial charge transfer channel is built at CeO2/CdSe interface and hot electrons of Au are injected into CdSe, efficiently augmenting carrier separation efficiency and carrier concentration. This study offers a referable strategy for designing photoanodes for efficient PEC hydrogen evolution from the perspective of interface energetics engineering and carrier injection.