Facile and Scalable Synthesis of “Caterpillar-like” ZnO Nanostructures with Enhanced Photoelectrochemical Water-Splitting Effect

Abstract

In an effort to replace conventional multistep seeding methods to produce multidimensional ZnO nanostructures with high spatial occupancy of nanowires (NWs), a rational and facile synthesis protocol for “caterpillar-like” branched ZnO nanofibers (BZNs) is reported. This process combined the scalable forcespinning technology with a hydrothermal process to efficiently develop BZNs to substantially enhance surface area and roughness factor. Specifically, unbranched ZnO nanofibers were first prepared by spinning polyvinylpyrrolidone (PVP)/zinc nitrate hexahydrate (Zn(NO3)2·6H2O) composite fibers, followed by calcination at 500 °C. These fibers were deposited on flat substrates to serve as nonwoven netlike seed sites for hydrothermal growth of ultradense and uniform NW branches to form “caterpillar-like” BZNs. Their usage as photoanodes in photoelectrochemical water-splitting cells was evaluated, resulting in a photon-to-hydrogen conversion efficiency of 0.165%, an enhancement of 147% when compared to ZnO NW a...