A ZnO@CuO core–shell heterojunction photoanode modified with ZnFe-LDH for efficient and stable photoelectrochemical performance

Abstract

In this study, we have designed and synthesized a novel ZnO@CuO core–shell heterojunction photoanode modified with cocatalyst ZnFe-layered double hydroxides (ZnFe-LDH). As expected, the deposition of CuO enhances light harvesting and shortens the diffusion distance for charge transfer. The ZnO@CuO heterojunction also enhances charge separation and suppresses recombination. Furthermore, modification with cocatalyst ZnFe-LDH facilitates photogenerated hole transport and accelerates the surface oxidation reaction kinetics. On account of the synergistic effect of the core–shell heterojunction in ZnO@CuO with cocatalyst ZnFe-LDH, this photoanode exhibits an optimal photocurrent density of 2.08 mA cm⁻² at 1.23 V vs. RHE, which is about 5.3 times that of the pristine ZnO photoanode. Therefore, the construction of ZnO@CuO core–shell nanorod arrays coupled with cocatalyst ZnFe-LDH provides an effective and novel route for designing low-cost and high-efficiency photoelectrodes.