Abstract：
Optimize the separation and transport mechanism of photogenerated carriers in heterojunction composites, and make full use of the active sites of each material are key factors to enhance photocatalytic activity. Herein, we successfully synthesize defective CdLa2S4@La(OH)3@Co3S4 (CLS@LOH@CS) Z-scheme heterojunction photocatalysts through a facile solvothermal method, which show broad-spectrum absorption and excellent photocatalytic activity. La(OH)3 nanosheets not only greatly increase the specific surface area of photocatalyst, but also can be coupled with CdLa2S4 (CLS) and form Z-scheme heterojunction by converting irradiation light. In addition, Co3S4 with photothermal properties is obtained by in-situ sulfurization method, which can release heat to improve the mobility of photogenerated carriers, and also be used as a cocatalyst for hydrogen production. Most importantly, the formation of Co3S4 leads to a large number of sulfur vacancy defects in CLS, and thus improving the separation efficiency of photogenerated electrons and holes, and increasing the catalytic active sites. Consequently, the maximum hydrogen production rate of CLS@LOH@CS heterojunctions can reach 26.4 mmol g-1h-1, which is 293 times than pristine CLS (0.09 mmol g-1h-1). This work will provide a new horizon for synthesizing high efficiency heterojunction photocatalysts through switching the separation and transport modes of photogenerated carrier.
摘要：
优化异质结复合材料中光生载流子的分离和传输机制，而充分利用各材料的活性位点是提高光催化活性的关键因素。在这里，我们通过简单的溶剂热法成功合成了有缺陷的CdLa2S4@La(OH)3@Co3S4(CLS@LOH@CS)Z型异质结光催化剂，具有广谱吸收和优异的光催化活性。La(OH)3纳米片不仅大大增加了光催化剂的比表面积,但也可以与CdLa2S4（CLS）耦合并通过转换照射光形成Z方案异质结。此外,通过原位硫化法获得具有光热性能的Co3S4，可以释放热量以提高光生载流子的迁移率，也可用作制氢的助催化剂。最重要的是,Co3S4的形成导致CLS中大量的硫空位缺陷,从而提高了光生电子和空穴的分离效率，并增加催化活性位点。因此,CLS@LOH@CS异质结的最大产氢速率可以达到26.4mmolg-1h-1，是原始CLS（0.09mmolg-1h-1）的293倍。这项工作将为通过切换光生载流子的分离和传输模式来合成高效异质结光催化剂提供新的视野。
