光辅助的醇类分子电氧化催化剂理性设计、可控构筑及耦合催化机理研究

In order to solve the problems of slow oxidation kinetics of alcohol in direct alcohol fuel cell, poisoning of Pt catalysts by COads and difficulty in breaking C-C bond of alcohol molecules above C2, photo-electro-thermal co-catalysis technology is employed in this project to promote the activation of alcohol molecules. We have proposed the optimization strategies of " organic-inorganic semiconductor heterojunction and metal-semiconductor schottky junction " nano-structure and " light trapping layer–interface layer–catalytic layer" structure for photo-electrocatalysts and photo-electrodes, respectively. Based on the theory and experiment, the high efficient alcohol oxidation photo-electro-catalyst and photoelectrode were fabricated by using the composite with structure of noble metal/organic dye molecule/transition metal oxide heterojunction. The activity and product distribution of photoelectrocatalytic alcohols oxidation were investigated by electrochemical method, micro-technique and on-line spectroscopic technique. The intrinsic structure-activity relationship was studied, and the reaction mechanism of photo-electro-thermal coupling catalysis was revealed. The feasibility and practicability of photo-assisted direct alcohol fuel cell were investigated. The research results of this project are expected to provide references for fuel cell catalysts and solar photo-electro conversion catalysts, and have important significance for expanding the application of photoelectro synergistic catalysis technology.

针对直接醇燃料电池中阳极醇氧化动力学慢，Pt催化剂COads毒化， C2以上醇分子C-C键难以断裂等关键问题，本项目拟利用光-电-热协同催化技术，高效活化醇分子。围绕光电催化剂和光电极分别提出“有机-无机半导体异质结和金属-半导体肖特基结”复合纳米结构和“捕光层-界面层-催化层”电极结构优化策略。结合理论和实验，构筑基于贵金属/有机染料分子/过渡金属氧化物异质结复合结构的高效醇氧化光电催化剂和光电极。采用电化学技术、显微和在线谱学技术，研究光电催化剂的构效关系，揭示光-电-热耦合催化的反应机制。构筑光辅助的直接醇燃料电池，考察光阳极的可行性和实用性。该项目的研究结果有望为燃料电池催化剂和太阳能光电转化催化剂提供参考，对拓展光电协同催化技术的应用具有有重要意义。

针对直接醇燃料电池中阳极醇氧化动力学慢，Pt催化剂COads毒化， C2以上醇分子C-C键难以断裂等关键问题，本项目利用光-电-热协同催化技术，高效活化醇分子，设计制备了多个高效醇氧化光电催化剂，系统研究了不同半导体氧化物载体对光电催化甲醇氧化的促进作用，并构筑光阳极，组装高性能光辅助的直接甲醇燃料电池。进一步，结合谱学、电化学技术等揭示了光电耦合催化作用本质，在WO3半导体表面，耦合过程对所施加的偏压具有依赖关系，在低偏压下，甲醇氧化主要依赖光生空穴的表面浓度；而在高偏压下光生空穴表面浓度达到极限，甲醇氧化电流的增加主要来自于铂表面的甲醇电氧化过程，光生空穴协助甲醇脱氢过程。而在BiVO4和V2O5半导体等则通过对水的活化氧化产生OH基，进而促进了甲醇在Pt表面的脱氢过程，加快反应速率。本项目为光电燃料电池的实用性和可行性提供了坚实的理论依据，对丰富催化学科基础理论具有一定的科学意义。.在该项目支持下，相关成果在本领域核心刊物发表SCI论文9篇，申请专利3件，授权2件，培养硕士2名。