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 H2 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 μmolcm−2 of H2 and 25.8 μmolcm−2 of O2 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 photogenerated carrier separation and enhanced oxygen evolution reactions on the anode surface.