AgFeS2 -Nanowire-Modified BiVO4 Photoanodes for Photoelectrochemical Water Splitting.

Photoelectrochemical water splitting is a promising and environmentally friendly route for the conversion of solar energy into hydrogen. However, the efficiency of this energy conversion process is low because of the limited light absorption and rapid bulk recombination of charge carriers. In this study, the combination of a novel ternary sensitizer AgFeS2 , having a narrow bandgap of 0.9 eV, with a BiVO4 electrode is presented for the enhancement of the solar-energy-to-hydrogen conversion efficiency. The photoelectrochemical properties of this combined material were investigated and the photocurrent densities of AgFeS2 -BiVO4 composite electrodes were greatly enhanced compared with pristine BiVO4 (15 times higher at 0.6 V vs. Ag/AgCl under AM 1.5G illumination). The enhanced photoelectrochemical properties arise from extended light absorption, fast charge transfer and appropriate energy gap alignment. It was demonstrated that AgFeS2 nanowires are promising inorganic sensitizers for improving the efficiency of solar water splitting.