Interfacial Engineering by VOx/m-TiO2 Films for Optimizing Photon-Generated Carrier to Boost Photoelectrochemical N2 Conversion to NH3

Optimal design of the photocathode is crucial and a meaningful approach for regulating many important photoelectrochemical (PEC) reactions. Interfacial engineering is substantiated as an effective tactic for tuning the direction of the internal carrier flow in thin-film semiconductor solar devices. Yet, so far, the type of PV device architecture involving in the interfacial transport layer is less adopted in photoelectrochemical (PEC) devices. Herein, the coupled VO_x/TiO₂ interfacial engineering brings in the construction of an integrated p-ZnTe hetero-structured photocathode, which was composed of a PN junction constructed with p-ZnTe and CdS, VO_x as the interface layer for hole transport, and m-TiO₂ as the scaffold layer. Compared with the simple PN structure, the photocathodes with the assembly of interfacial engineering enable advances in the combination of apparent quantum efficiency (AQE: 0.6%) and better yield (6.23 μg h^-1 cm^-2) on photoelec-N₂ conversion to NH₃. Interfacial engineering and heterojunction construction effects synergistically optimize photoexcited carriers and the separation and transformation at the interface. This favors easier migration of holes to the back and the assembly of electrons on the surface, achieving the intensive charge separation and surface charge injection efficiency of photogenerated carriers. Our work represents a new enlightenment for building thin-film photocathode architectures to boost the effectiveness on solar-driven utilization.