Wittichenite semiconductor of Cu(3)BiS(3) films for efficient hydrogen evolution from solar driven photoelectrochemical water splitting

A highly efficient, low-cost and environmentally friendly photocathode with long-term stability is the goal of practical solar hydrogen evolution applications. Here, we found that the Cu(3)BiS(3) film-based photocathode meets the abovementioned requirements. The Cu(3)BiS(3)-based photocathode presents a remarkable onset potential over 0.9 V(RHE) with excellent photoelectrochemical current densities (~7 mA/cm(2) under 0 V(RHE)) and appreciable 10-hour long-term stability in neutral water solutions. This high onset potential of the Cu(3)BiS(3)-based photocathode directly results in a good unbiased operating photocurrent of ~1.6 mA/cm(2) assisted by the BiVO(4) photoanode. A tandem device of Cu(3)BiS(3)-BiVO(4) with an unbiased solar-to-hydrogen conversion efficiency of 2.04% is presented. This tandem device also presents high stability over 20 hours. Ultimately, a 5 × 5 cm(2) large Cu(3)BiS(3)-BiVO(4) tandem device module is fabricated for standalone overall solar water splitting with a long-term stability of 60 hours.