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

[Display omitted] • Ultrathin and single crystal of WO 3 nanoplates synthesized by a one-step hydrothermal technique. • This study shows a collaborative approach of facet engineering and p-n Junction of WO 3 /MoS 2 -MoO X. • Depth, surface, and interface of the WO 3 /MoS 2 -MoO X investigated by TOF-SIMS analysis. • The obtained WO 3 /MoS 2 -MoO X photoanode exhibits highly efficient and stable PEC H 2 generation. • H 2 and O 2 productions of the WO 3 /MoS 2 -MoO X after 2 h were 54.5 and 25.8 μmol cm−2, respectively. In this paper, we demonstrate a facet-controlled WO 3 nanoplate heterojunction with MoS 2 -MoO X 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 WO 3 photoanode and drop-casting process of the MoS 2 nanosheets (4, 8, and 12 times) to obtain the optimum amount of the material (MoS 2 and MoO X) for the PEC performance of the WO 3 /#n-MoS 2 and WO 3 /#n-MoS 2 -MoO X (n = 4, 8, and 12) photoanodes were investigated. The photocurrent density of the WO 3 /MoS 2 -MoO X 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 WO 3 and WO 3 /MoS 2 photoelectrodes, respectively. The incident photon current efficiency of the WO 3 /MoS 2 -MoO X photoanode is approximately 27.5%, which is a significant improvement over that of bare WO 3. The WO 3 /MoS 2 -MoO X photoanode produced 54.5 μmolcm−2 of H 2 and 25.8 μmolcm−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 WO 3 /MoS 2 -MoO X photoanode, which was developed through simple and facial drop casting of MoS 2 nanosheets onto WO 3 photoanode, resulted in effective photogenerated carrier separation and enhanced oxygen evolution reactions on the anode surface. [ABSTRACT FROM AUTHOR]