One-pot synthesis of S-scheme MoS/g-CN heterojunction as effective visible light photocatalyst.

Despite pioneering as the holy grail in photocatalysts, abundant reports have demonstrated that g-CN performs poor photocatalytic activity due to its high recombination rate of photo-induced charge carriers. Many efforts have been conducted to overcome this limitation in which the semiconductor-semiconductor coupling strategies toward heterojunction formation were considered as the easiest but the most effective method. Herein, a one-pot solid-state reaction of thiourea and sodium molybdate as precursors at different temperatures under N gas was applied for preparing composites of MoS/g-CN. The physicochemical characterization of the final products determines the variation in contents of components (MoS and g-CN) via the increase of synthesis temperature. The enhanced photocatalytic activity of the MoS/g-CN composites was evaluated by the degradation of Rhodamine B in an aqueous solution under visible light. Therein, composites synthesized at 500 °C showed the best photocatalytic performance with a degradation efficiency of 90%, much higher than that of single g-CN. The significant improvement in photocatalytic performance is attributed to the enhancement in light-harvesting and extension in photo-induced charge carriers' lifetime of composites which are originated from the synergic effect between the components. Besides, the photocatalytic mechanism is demonstrated to well-fit into the S-scheme pathway with apparent evidences.