Boosting Water Splitting Performance of BiVO4 Photoanode through Selective Surface Decoration of Ag2S

The unsatisfactory of solar absorption and charge separation is the main loss limiting the conversion efficiency in photoelectrochemical water splitting system. Here, Ag2S/BiVO4 heterostructure have been fabricated for the first time to PEC splitting water, achieving efficient solar-to-chemical energy conversion. The Ag2S nanoparticles evenly distributing on the surface of BiVO4 not only promotes the charge separation, but also greatly facilitates the surface hole injection. The results show that the optimal Ag2S/BiVO4 heterostructure reach a remarkable photocurrent density of 1.91 mA/cm(2) at 1.23 V (vs RHE) under 100 mW/cm(2) irradiation, which is approximately 3.2-fold higher than that of bare BiVO4. The incident photon-to-current efficiency (IPCE) of Ag2S/BiVO4 heterostructure have been enhanced up to 23 % in visible region (V-bias=1.23 V, 460 nm). In addition, Ag2S/BiVO4 shows the attracting stability during photoelectrochemical process, since its photocurrent density can keep for 92 % after 2 h. The charges transfer mechanism for Ag2S/BiVO4 heterostructure were also proposed. This work provides a new insight for constructing efficient and stable photoanodes based on BiVO4.