Interfacial charge kinetics of ZnO/ZnTe heterostructured nanorod arrays for CO2 photoreduction

Constructing p-n heterojunction system is promising in achieving high performance materials for photocatalysis application. Studying the charge dynamics across the interface is instructive in interpreting the performance and providing approaches for further improvement. ZnO/ZnTe heterostructured nanorod arrays for CO2 photoreduction are prepared via a simple electrochemical deposition approach. X-ray diffraction and transmission electron microscopy confirm successful construction of the ZnO/ZnTe heterojunction. The charge dynamics are studied by various photoelectrochemical (PEC) characterizations, the results of which indicate that the deposition of ZnTe is in favor of the charge kinetics like generation and transfer, and the PEC performance increases with the raise of the ZnTe amount. Mott-Schottky plots are employed to probe the mechanism of the PEC performance, based on which the interfacial space charge region is thoroughly discussed too. An electronic band structure model of the ZnO/ZnTe heterostructure electrode in the aqueous solution is thus put forward, which may promote the understanding of the relevant charge transfer. Finally, the ZnO/ZnTe heterostructure is applied for photocatalytic reduction of CO2, and the 8 h-CH4 yield can reach 0.04 mu mol/cm(2) for ZnO/ZnTe prepared with deposition time of 3 min for ZnTe. (C) 2018 Elsevier Ltd. All rights reserved.