NiO/CoOX(X=P, S和Te)复合功能催化剂活性位相界面调控增强尿素电解制氢性能研究

研制高效的非贵金属催化剂催化尿素氧化是发展尿素电解制氢和直接尿素燃料电池技术的关键。然而，现有催化剂仍面临活化活性位少和易中毒失活的问题。鉴于尿素分子中分解生成N2的氨基是供电子基团，生成CO2的羰基是吸电子基团，本项目提出设计构建具有缺电子与富电子特性的双活性位复合功能催化剂NiO/CoOX(X=P, S和Te)。通过调控CoO晶体结构（非晶态、面心立方和六方密堆相）及CoOX(X=P, S和Te)的取代程度，利用界面工程形成可与氨基和羰基匹配的缺电子和富电子双活性位相界面，研究不同晶相结构产生的配位不饱和钴和多价电子非金属诱导氧化镍界面局域畸变的影响规律；分析电子转移形成的界面区缺电子NiOOH与富电子CoOX(X=P, S和Te)对氨基和羰基的识别和选择性吸附；阐明其与活性和抗中毒稳定性间的构效关系。本研究工作可为开发高效尿素电解制氢和其它有机电氧化催化剂提供新的设计思路和理论指导。

Designing high-efficient non-noble metal catalysts for electrocatalytic urea oxidation reaction (UOR) has been one of the major challenges for promoting the urea electrolysis and development of direct urea fuel cells. However, traditional catalysts cannot satisfy the demand of urea electrolysis due to the lack of enough active sites and unfavorably strong binding of active sites with intermediates. Since the amino group oxidized to N2 is the electron-donating group and the carbonyl group oxidized to CO2 is the electron-withdrawing in urea molecule, herein, we will propose construction of composite functional catalysts NiO/CoOX(X=P, S and Te) with double active sites of deficient electron and rich electron. The crystal phase structure of CoO (amorphous, face centered cubic and hexagonal closed packed phase) will be regulated, as well as the degree of substitution of CoOX (X=P, S and Te). Interface engineering is used to form double active sites of deficient electron and rich electron that can be matched with amino and carbonyl groups. The unsaturated Co from different crystal CoO and abundant valence electrons from nonmetals induce the distortion of crystal structure in the interfaces of NiO and CoO, promoting the formation of more highly active interface regions. The formed electron-deficient NiOOH and electron-rich CoOX(X=P, S and Te) will selectively adsorb and activate amino and carbonyl groups. The influence on the UOR activity and stability of the as-synthesized NiO/CoOX(X=P, S and Te) will be systematically investigated. In summary, this project will enrich the theory of high-efficient oxidation of urea and provide a solid scientific guideline for designing and optimizing high-efficient catalysts for other organic electrooxidation.