To solve serious energy and environmental crises caused by rapid industrial development, the formation of Z-scheme heterostructured photocatalysts is a promising approach for efficient and scalable H₂ production from water splitting due to wide absorption range, high charge-separation efficiency and strong redox ability of the Z-scheme heterostructured photocatalysts. In this study, we combined the MOFs of NH₂-MIL-125(Ti) with g-C₃N₄ functionalized by benzoic acid (CFB) to synthesize a novel composite catalyst of CFB/NH₂-MIL-125(Ti) (CFBM) by covalent bonds for the first time. The benzoic acid in the CFBM acts as electron mediator to well separate photogenerated electrons and holes, leading to excellent photocatalytic performance of photocatalytic hydrogen generation from water splitting under visible light irradiation. Experimental results show that the H₂ production rate of the 10CFBM is 1.123 mmol·h⁻¹·g⁻¹, which is about 6 times of the NH₂-MIL-125(Ti). Meanwhile, the simple physical mixture of NH₂-MIL-125(Ti) with 10 wt% g-C₃N₄ and the 10wt%g-C₃N₄/MOFs heterostructured catalyst all show much smaller H2 evolution rate and worse stability than that of the 10CFBM. Finally, we proposed a possible mechanism to well explain the improved photocatalytic performance of the Z-scheme photocatalytic system based on the results of different characterizations. The present work gives a good example to develop a novel Z-scheme heterostructured system with good stability and high photocatalytic activity for H₂ evolution and puts forward a new synthetic strategy to prepare metal-free semiconductor/MOFs formed by covalent bonds.

为解决因工业快速发展而引起的严重能源和环境危机，由于吸收范围广，电荷分离效率高和强大的氧化还原能力，形成Z型异质结构光催化剂是从水分解中高效且可扩展生产H _2的一种有前途的方法。Z方案异质结构光催化剂的制备。在这项研究中，我们结合了NH ₂ -MIL-125（Ti）的MOF和被苯甲酸（CFB）功能化的gC ₃ N ₄，合成了一种新型的CFB / NH ₂复合催化剂。-MIL-125（Ti）（CFBM）首次通过共价键连接。CFBM中的苯甲酸充当电子介质，可以很好地分离光生电子和空穴，从而在可见光照射下从水分解产生的光催化氢产生优异的光催化性能。实验结果表明，10CFBM的H ₂生成速率为1.123 mmol·h ^-1 ·g ^-1，约为NH ₂ -MIL-125（Ti）的6倍。同时，NH ₂ -MIL-125（Ti）与10 wt％gC ₃ N ₄和10wt％gC ₃ N ₄的简单物理混合物/ MOFs异质结构催化剂均显示出比10CFBM小得多的H2释放速率和更差的稳定性。最后，基于不同的表征结果，我们提出了一种可能的机制来很好地解释Z方案光催化体系的改进的光催化性能。目前的工作给出一个很好的例子，开发具有良好的稳定性和高的光催化活性为h的新颖Z-方案异质结构系统₂演化和提出了一种新的合成策略以制备通过共价键形成的不含金属的半导体/ MOFs材料。