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

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)center dot 6H(2)O) composite fibers, followed by calcination at 500 degrees 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 arrays with similar dimensions. An enhanced light-harvesting process coupled with a facile and scalable synthetic procedure is presented.