Tuning the Carrier Transfer Behavior of Coaxial ZnO/ZnS/ZnIn2S4 Nanorods with a Coherent Lattice Heterojunction Structure for Photoelectrochemical Water Oxidation

Serious degradation and the short photogenerated carrier lifetime for the wide-bandgap semiconductor ZnO have become prominent issues that negatively affect photoelectrochemical (PEC) water splitting. Herein, a novel electron transport pathway was constructed by simple but effective coaxial growth of ZnO/ZnS/ZnIn2S4 heterostructure nanoarrays to increase the carrier separation efficiency. This new photoanode fulfilled the requirements of both favorable band alignment and stability, achieving a stable photocurrent density of 1.146 mA cm(-2) at 1.2 V-RHE, which was approximately twice that of pristine ZnO. Detailed experimental studies revealed that the improved PEC activity was due to the lattice-matching interface coherency that activated the carrier transport pathway, giving rise to an optimized interfacial electronic structure for promoted charge separation by the built-in electric field and strengthened water oxidation activity. This design may provide a new approach to fabricating various efficient lattice-matching coherent interface photoanodes for PEC water splitting.

Automated summary

A novel electron transport pathway was constructed by growing ZnO/ZnS/ZnIn2S4 heterostructure nanoarrays coaxially, which increased carrier separation efficiency. This new photoanode fulfilled the requirements of favorable band alignment and stability, achieving a stable photocurrent density and may provide a new approach for fabricating efficient photoanodes for PEC water splitting.