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

Graphical Gloves on : A ZnO/ZnS/ZnIn 2 S 4 (ZnO/ZnS/ZIS) photoanode is fabricated by simple but effective sequential ion-exchange reactions. The prepared coaxial “glove” structure photoanode facilitates protection of the inner layer of ZnO, simultaneously boosting charge separation and the oxygen evolution reaction kinetics and achieving a stable photocurrent density of 1.146 mA cm −2 at 1.2 V RHE , approximately 2-fold higher than that of pristine ZnO. 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/ZnIn 2 S 4 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.