Post-treatment with ZnFe2O4 Nanoparticles to Improve Photo-Electrochemical Performance of ZnO Nanorods Based Photoelectrodes

The ZnFe2O4 nanoparticles (ZNF NPs) modified ZnO nanorods (NRs) have proven to be an effective strategy to enhance photoelectrochemical water splitting applications. Hierarchical ZNF/ZnO NRs with ZnO NRs and ZNF NPs were successfully prepared by a facile sol-gel spin coating and hydrothermal method. Noticeably, the wettability of ZNF/ZnO nanostructures can be modified by changing the immersion time in ZNF NPs solution. The bare ZnO NRs showed a photocurrent density of 0.10 mA/cm(2) for potential value of 0.5V vs. Ag/AgCl. In contrast, ZNF/ZnO nanostructured samples showed an enhanced linear increase of the photocurrent density of 1.15 mA/cm(2) with an applied potential of 0.5V. An optimum amount of ZNF NPs on the ZnO NRs enhanced the photocurrent density more than 10 times and the photo-conversion efficiency more than 10 times compared to those of the bare ZnO NRs. This optimized sample has a lower charge recombination rate due to increase in transition decay time by 2 times compared to bare ZnO NRs samples. The photocurrent enhancement was induced by increase of photo-generated electron-hole separation and improved charge transfer of photo-generated carriers, which reduces recombination and hence can be applied for photo-electrochemical water splitting application.