FeVO4 Nanopolyhedron Photoelectrodes for Stable and Efficient Water Splitting

Crystalline FeVO4 nanopolyhedron (FVO NPH) photoelectrodes are successfully prepared by using an in situ solid-state transformation from hydrothermal FeOOH films via adding vanadium precursor and following thermal treatments. The FVO NPH photoelectrodes possess uniformly dispersed polyhedral nanocrystals that directly grow on the conductive substrate with tunable film thicknesses. The unique morphology enables an outstanding photo-electrocatalytic performance, and the optimized FVO NPH photoelectrode, which was annealed at 550 degrees C for 4 h with a film thickness of similar to 560 nm, exhibits excellent photocurrent densities of similar to 0.47 and similar to 0.68 mA cm(-2) at 1.0 and 1.2 V vs. Ag/AgCl, respectively. After decorating CoPi co-catalyst, FVO/CoPi shows a highly efficient water splitting performance with O-2 and H-2 evolution rates of 7.53 and 15.32 mu mol cm(-2) h(-1), respectively, which are similar to 1.88 and similar to 1.80 times, respectively, of these of the FVO NPH. The proposed photoelectrodes also show excellently chemical and physical stabilities in solar water splitting. This is the first time reported the preparation of well-organized nanostructured FeVO4 films, which warrants further optimization studies on morphologies and compositions of FeVO4-based photoelectrodes.

Automated summary

FeVO4 nanopolyhedron photoelectrodes prepared through hydrothermal synthesis and thermal treatment exhibit excellent photo-electrocatalytic performance with uniformly dispersed nanocrystals, offering tunable film thicknesses and promising potential for further optimization studies.