Construction of a noble-metal-free MoS₂/ZnO-g-C₃N₄ ternary nanocomposite for enhanced charge separation and transfer toward highly efficient photocatalytic water splitting

The development of high-efficiency photocatalysts with enhanced photocharge separation and transfer capabilities is critical for harnessing renewable energy sources to drive photocatalytic hydrogen (H₂) production. Carbonaceous materials have emerged as promising, cost-effective co-catalysts to replace some traditionally expensive noble metal in photocatalytic water splitting because of their unique properties. This study introduces an innovative ternary nanocomposite catalyst consisting of molybdenum disulphide, zinc oxide, and graphitic carbon nitride (MoS₂/ZnO-g-C₃N₄) (MZ-CN), synthesized through a three-step process combining three steps were used to create this catalyst: coprecipitation, ball milling, and wet impregnation. The primary objective of this research is first time to evaluate the H₂ generation performance of this ternary nanocomposite. A comprehensive of analytical techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), high resolution transmission electron microscopy (HR-TEM), scanning electron microscopy (SEM), UV-Vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) surface area analysis, and transient photocurrent response measurements and electrochemical impedance spectroscopy measurements (EIS) were used to conduct systematic characterizations. Sodium sulfite (Na₂SO₃) and sodium sulphide (Na₂S) were used as sacrificial reagents to replicate solar light irradiation and assess photocatalytic H₂ production. The optimized 9MZ-12CN catalyst (9% MoS₂/ZnO-12% g-C₃N₄) demonstrated a remarkable H₂ evolution rate of 3612 μmol h⁻¹g⁻¹. This performance represents a 9.2-fold enhancement over pristine g-C₃N₄ and a 4-fold enhancement over 9% MoS₂/ZnO. This H₂ evolution rate is the highest documented for a ternary nanocomposite based on g-C₃N₄ under solar radiation simulation. Moreover, the 9MZ-12CN photocatalyst demonstrated excellent stability over five reaction cycles. This research gives valuable information about scheming effective, noble metal-free g-C₃N₄-based photocatalysts, which can significantly support the transition to solar-powered hydrogen production. A suggested mechanism for the H₂ generation process of the MoS₂/ZnO-g-C₃N₄ photocatalysts involves a Z-scheme charge transfer pathway.