A direct Z-scheme MoS₂/NiWO₄ heterojunction system was successfully fabricated using conventional hydrothermal method for photoelectrochemical (PEC) water splitting under simulated solar light. The fabricated system showed superb activity with applied bias photon-to-current efficiency (ABPE) up to 0.12%, which is too high to be compared with that achieved by pristine NiWO₄ NPs (8.02 × 10^-5 %), and 4 times larger than pristine MoS₂ (0.03%). It was also found that the constructed Z-scheme MoS₂/NiWO₄ showed a high photocurrent density of 1.2 mA/cm², which is ~ 8.1 and 2.4 times as high as that of the NiWO₄, and MoS₂, respectively. Moreover, MoS₂/NiWO4 heterojunction showed excellent photocurrent stability of almost 46 min with the lowest onset potential of 0.744 V_RHE, which shifts ~ 312 mV, and 145 mV cathodically relative to pristine NiWO₄, and MoS₂ respectively. The remarkably enhanced PEC water splitting performance could be attributed to the efficient electron-hole pairs separation and the higher redox capability of the photo-induced charges in the constructed Z-scheme heterojunction. It can also be attributed to the excellent improvement of visible light absorption in the constructed heterojunction. The current results provide meaningful guidance for the fabrication of direct Z-scheme layered transition metal dichalcogenides systems, which are promising for water splitting under visible light irradiation and related applications.

Ibrahim Khan

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