Herein, the metallic Ti₃C₂ nanosheets decorated 2D-2D Zn_0.7Cd_0.3S (ZCS)-Fe₂O₃ Ohmic/step-scheme (S-scheme) hybrid heterojunction with cascade 2D coupling interfaces was rationally synthesized by oil bath and hydrothermal methods. The construction of both S-scheme and Ohmic heterojunctions was identified via in-situ irradiation XPS (ISI XPS), Electron spin resonance (ESR) or ultraviolet photoelectron spectroscopy (UPS) experiments, which can greatly improve the photocatalytic H₂ evolution raction (HER) rate and stability. The H₂ evolution rates of ZCS/0.5 Ti₃C₂, ZCS/2 Fe₂O₃ and ZCS/0.5 Ti₃C₂/2 Fe₂O₃ were 1.91, 2.0 and 6.35 times higher than that of pure ZCS nanosheets (NSs), respectively. The optimized ternary composite exhibits a highest HER activity of 27.24 mmol g^-1 h^-1, with an apparent quantum efficiency of 20.92% at 450 nm. Meanwhile, the ternary photocatalyst still exhibited much higher stability. Clearly, the strong S-scheme interfacial electric fields could effectively promote spatial charge separation between ZCS nanosheets and Fe₂O₃ nanosheets, while 2D Ti₃C₂ MXene nanosheets, as an Ohmic-junction H₂-evolution co-catalyst, could provide more electron transfer pathways and a large number of active sites for photocatalytic HER. It is expected that this work can offer some new idea or inspirations to rationally design highly efficient S-scheme heterojunction photocatalysts for further practical applications.

在此，金属 Ti ₃ C ₂纳米片装饰 2D-2D Zn _0.7 Cd _0.3 S (ZCS)-Fe ₂ O ₃ Ohmic/step-scheme (S-scheme) 具有级联 2D 耦合界面的杂化异质结通过油浴和水热法。通过原位辐射XPS（ISI XPS）、电子自旋共振（ESR）或紫外光电子能谱（UPS）实验确定了S型和欧姆异质结的构建，这可以大大提高光催化H ₂演化反应（HER） ) 率和稳定性。ZCS/0.5 Ti ₃ C ₂、ZCS/2 Fe的H ₂析出率₂ O ₃和ZCS/0.5 Ti ₃ C ₂ /2 Fe ₂ O ₃分别比纯ZCS纳米片（NSs）高1.91、2.0和6.35倍。优化后的三元复合材料表现出最高的 HER 活性为 27.24 mmol g ^-1 h ^-1，在 450 nm 处的表观量子效率为 20.92%。同时，三元光催化剂仍然表现出更高的稳定性。显然，强 S 型界面电场可以有效地促进 ZCS 纳米片和 Fe ₂ O ₃纳米片之间的空间电荷分离，而 2D Ti ₃ C ₂MXene 纳米片作为欧姆结 H ₂演化助催化剂，可以为光催化 HER 提供更多的电子转移途径和大量的活性位点。预计这项工作可以为合理设计高效的S型异质结光催化剂以进一步实际应用提供一些新的思路或灵感。