Highly efficient and stable WO3/MoS2-MoOX photoanode for photoelectrochemical hydrogen production; a collaborative approach of facet engineering and P-N junction

Abstract

In this paper, we demonstrate a facet-controlled WO3 nanoplate heterojunction with MoS2-MoOX nanosheets that produces extremely efficient and stable photoelectrochemical H-2 production. Furthermore, the effect of the hydrothermal process time (t = 1, 2, and 3 h) for the WO3 photoanode and drop-casting process of the MoS2 nanosheets (4, 8, and 12 times) to obtain the optimum amount of the material (MoS2 and MoOX) for the PEC performance of the WO3/#n-MoS2 and WO3/#n-MoS2-MoOX (n = 4, 8, and 12) photoanodes were investigated. The photocurrent density of the WO3/MoS2-MoOX photoanode was approximately 2.15 mA.cm(2) at 1.23 V vs. RHE, which was 8.6 and 1.2 times higher compare to pure WO3 and WO3/MoS2 photoelectrodes, respectively. The incident photon current efficiency of the WO3/MoS2-MoOX photoanode is approximately 27.5%, which is a significant improvement over that of bare WO3. The WO3/MoS2-MoOX photoanode produced 54.5 mu molcm(-2) of H-2 and 25.8 mu molcm(-2) of O-2 after 2 h, at 1.23 V vs. RHE and 100 mWcm(-2). The electrochemical kinetics clearly showed that water oxidation reaction was accelerated. The WO3/MoS2-MoOX photoanode, which was developed through simple and facial drop casting of MoS2 nanosheets onto WO3 photoanode, resulted in effective photo-generated carrier separation and enhanced oxygen evolution reactions on the anode surface.