Simultaneous Enhancement of Charge Separation and Hole Transportation in a W:α-Fe₂O₃/MoS₂ Photoanode: A Collaborative Approach of MoS₂ as a Heterojunction and W as a Metal Dopant

In this study, a facile approach has been successfully applied to synthesize a W-doped Fe 2 O 3 /MoS 2 core–shell electrode with unique nanostructure modifications for photoelectrochemical performance. A two-dimensional (2D) structure of molybdenum disulfide (MoS 2 ) and tungsten (W)-doped hematite (W:α-Fe 2 O 3 ) overcomes the drawbacks of the α-Fe 2 O 3 and MoS 2 semiconductor through simple and facile processes to improve the photoelectrochemical (PEC) performance. The highest photocurrent density of the 0.5W:α-Fe 2 O 3 /MoS 2 photoanode is 1.83 mA·cm –2 at 1.23 V vs reversible hydrogen electrode (RHE) under 100 mW·cm 2 illumination, which is higher than those of 0.5W:α-Fe 2 O 3 and pure α-Fe 2 O 3 electrodes. The overall water splitting was evaluated by measuring the H 2 and O 2 evolution, which after 2 h of irradiation for 0.5W:α-Fe 2 O 3 /MoS 2 was determined to be 49 and 23.8 μmol.cm –2, respectively. The optimized combination of the heterojunction and metal doping on pure α-Fe 2 O 3 (0.5W:α-Fe 2 O 3 /MoS 2 photoanode) showed an incident photon-to-electron conversion efficiency (IPCE) of 37% and an applied bias photon-to-current efficiency (ABPE) of 26%, which are around 5.2 and 13 times higher than those of 0.5W:α-Fe 2 O 3, respectively. Moreover, the facile fabrication strategy can be easily extended to design other oxide/carbon-sulfide/oxide core–shell materials for extensive applications.