In situ fabrication of Z-scheme C₃N₄/Ti₃C₂/CdS for efficient photocatalytic hydrogen peroxide production

Photocatalysis is a potential technology to produce hydrogen peroxide with low energy consumption and no pollution. However, when using traditional photocatalysts it is hard to meet the requirements of wide visible light absorption, high carrier separation rate and sufficient active sites. Graphitic carbon nitride (g-C₃N₄) has great potential in the photocatalytic production of hydrogen peroxide, but its photocatalytic performance is limited by a high carrier recombination ratio. Here, we fabricated the Z-Scheme heterojunction of C₃N₄/Ti₃C₂/CdS in situ. The large specific surface area of C₃N₄ can provide plenty of reactive sites, and the absorption efficiency under visible light is improved with the addition of Ti₃C₂ and CdS. The better conductivity of Ti₃C₂ reduces the charge transfer resistance. With the increase of surface charge carriers, the width of the space charge region decreases and the photocurrent density increases significantly. Under visible light irradiation, the H₂O₂ yield of the ternary photocatalyst reaches 256 μM L^-1 h^-1, which is about 6 times that of pristine C₃N₄. After three cycles, the high photocatalytic efficiency can still be maintained. In this paper, the reaction mechanism of photocatalytic hydrogen peroxide production by the C₃N₄/Ti₃C₂/CdS composite material is proposed through an in-depth study of energy band theory, which provides a new reference for the design and preparation of high-performance materials for photocatalytic hydrogen peroxide production.