TP-COFs/Pb3(CO3)2(OH)2复合材料二氧化碳还原光催化剂的构筑及性能研究

Construction and Photocatalytic Carbon Dioxide Reduction Performance of a TP-COFs/Pb3（CO3）2（OH）2 Composite

摘要:

光催化二氧化碳还原是将二氧化碳转化为燃料或化工原料,以应对环境污染与能源危机的一种可持续有效策略。然而，该过程中的还原产物选择性较低这一问题亟待解决。共价有机框架（COFs）材料，因具有高比表面积、高孔隙率、结构可调性和强可见光吸收能力等优势，近年来在光催化领域中受到广泛的关注。由于COFs材料缺少二氧化碳还原所需的活性位点，因此限制了其实际应用。碱式碳酸铅（Pb₃(CO₃)₂(OH)₂）作为一种高选择性电催化剂,可有效地将二氧化碳还原生成甲酸盐，并将其引入COFs体系中，从而提升体系的催化性能。首先在无氧高温条件下，采用油浴法合成TP-COFs，然后通过原位光化学与湿化学反应，将Pb₃(CO₃)₂(OH)₂负载于TP-COFs上，最终制备出TP-COFs/Pb₃(CO₃)₂(OH)₂复合材料。利用X射线衍射和扫描电子显微镜对TP-COFs/Pb₃(CO₃)₂(OH)₂复合材料进行表征，发现该复合材料为两相良好接触的片状材料；通过微量气体分析系统配备气相色谱仪测试发现，该复合材料在二氧化碳还原制甲酸盐的过程中表现出优异的效率和选择性，甲酸盐产率高达28.5 mmol?g^-1?h^-1，选择性超过99%。光催化二氧化碳还原制备甲酸盐的策略，为未来开发高效光催化提供了重要参考，并为实现二氧化碳资源利用开辟了新路径。

Abstract:

Photocatalytic CO₂ reduction to fuels or chemical feedstocks offers a sustainable approach to addressing global environmental and energy challenges. However， the low selectivity of current systems hinders their practical application. Covalent organic frameworks （COFs）， characterized by high specific surface area， porosity， structural turnability， and strong visible-light absorption， have emerged aspromising candidates for high efficient photocatalysts. Yet， the lack of active sites for CO₂ limits their performance. Pb₃（CO₃）₂（OH）₂， a proven electrocatalyst with high selectivity for CO₂ reduction to formate， can serve as a co-catalyst to enhance this reaction. In this study， TP-COFs were synthesized via oil bath method under high temperature， oxygen-free conditions. Subsequently， the TP-COFs/Pb₃（CO₃）₂（OH）₂ composites were obtained by loading Pb₃-（CO₃）₂（OH）₂ onto TP-COFs through successive in-situ photochemical and wet chemical reactions in the aqueous dispersion solution of TP-COF. Characterization using X-ray diffraction and scanning electron microscopy revealed the formation of microsheet materials with strong interfacial contact between the two phases. Performance testing with a trace gas analysis system and gas chromatograph demonstrated that the composite exhibited outstanding photocatalytic efficiency and selectivity for CO₂ reduction to formate， achieving a yield of 28.5 mmol?g^-1?h^-1 and a selectivity exceeding 99%. This work introduces a novel approach to designing and synthesizing highly efficient and selective photocatalyst for CO₂ reduction to formate， enabling effective CO₂ conversion. The findings provide valuable insights and a feasible pathway for the development of advanced photocatalytic systems for sustainable CO₂ utilization.