Due to the ability of cocatalysts to form heterojunctions on the surface in contact with g?C₃N₄, promoting the migration of photo generated electrons and enhancing the photocatalytic performance of g?C₃N₄, the introduction of cocatalysts plays a significant role in improving the photocatalytic activity of g?C₃N₄. Common co?catalysts can be broadly categorized into three groups: transition metal?based cocatalysts (non?precious?metal co?catalysts), precious metal based co?catalysts, and non?metal cocatalysts. Among them, transition metal?based cocatalysts have attracted widespread attention due to their low cost and strong ability to capture electrons. This article focuses on the composite methods, mechanisms of action, and their effects on the photocatalytic performance of various transition metal based cocatalysts (such as metal oxides, sulfides, phosphides, etc.) with g?C₃N₄, aiming to provide comprehensive theoretical and practical guidance for the design and development of efficient g?C₃N₄ based photocatalysts.

OA?ZnCl₂/SG supported catalyst was synthesized by sol?gel process using octanoic acid?zinc chloride deep eutectic solvents (OA?ZnCl₂ DESs) as additive. The structure of the catalyst was analyzed by infrared spectroscopy, X?ray diffraction, N₂ adsorption?desorption and scanning electron microscopy. The performance of oxidative desulfurization was studied by using OA?ZnCl₂/SG as adsorbent and catalyst, and hydrogen peroxide as oxidant. The loading dose of DESs, reaction temperature, n(H₂O₂)/n(S) ratio, the amount of catalyst and the effect of different sulfides on desulfurization rate were investigated. The results show that the desulfurization rate of the catalyst reaches 95.6% under the optimal conditions, and after 5 cycles, the desulfurization rate drops to 89.7%.