Low-Cost Oriented Hierarchical Growth of BiVO4/rGO/NiFe Nanoarrays Photoanode for Photoelectrochemical Water Splitting

A unique BiVO4/reduced graphene oxide (rGO)/NiFe hydroxide photoanode with oriented hierarchical nanostructure was fabricated via a facile and scalable solution route. Microstructure analysis shows that the ternary nanocomposite system presented a nanopyramid configuration with BiVO4 nanoarrays coated by sheetlike graphene interlayer and amorphous NiFe hydroxides. A maximum photocurrent density of 1.30 mA/cm(2) at scan rate of 20 mV/s at 1.23 V vs reversible hydrogen electrode was obtained for the BiVO4/rGO/NiFe photoelectrode, which was almost three times as high as that of pristine BiVO4. A boost of photocurrent density was achieved as a result of the synergistic effects between graphene shuttle interlayer and NiFe-based nanoarrays cocatalyst outer layer. Herein, rGO acts as an intermediate layer facilitating transfer of the photogenerated charge carriers, improving the adhesion of NiFe nanoarrays cocatalyst layer on the substrate and enhancing the stability and photoelectrochemical response of photoanode. This work demonstrates that tunable multicomponent design and rational hierarchical structure control are efficient approaches to enhance the photoelectrochemical water splitting performance of photoelectrode.