过渡金属碳化物对尿素电氧化催化剂活性组分NiOOH生成及稳定的共强化机制研究

尿素电解制氢及直接尿素燃料电池系统为含尿素废水（如尿液）的绿色处理及资源化利用提供有效途径，且有望在受限空间（航天及核潜艇等领域）发挥巨大潜力。然而，尿素电氧化Ni基催化剂活性低且稳定性差极大地限制了其应用。本项目针对其本质问题活性组分NiOOH难于生成且易中毒失活，借助电化学原位红外等手段探明毒化物种，基于过渡金属碳化物（TMCs）的双重特性对Ni进行改性：利用其较宽未占据d带调控Ni的d带态密度从而更易生成NiOOH，利用其类贵金属性调变催化剂表面对毒化物种的吸附能从而增强抗中毒性。借助量子化学计算与多种表征测试手段相结合，系统探究TMCs种类特性对Ni的d带态密度及对毒化物种吸附能的调控规律，揭示TMCs对NiOOH生成及稳定共强化机制，阐明Ni与TMCs相互作用对催化剂表面电子结构与尿素电氧化活性与稳定性间的构效关系，为理性构筑高效且稳定Ni/TMCs尿素电氧化催化剂提供科学依据。

Urea electrolysis producing hydrogen production and direct urea fuel cell systems, which provide effective ways for green treatment and resource utilization of urea wastewater (as urine), further expecting to play great potentials in restricted space (such as aerospace and nuclear submarine). However, the low activity and poor stability of Ni-based catalysts for urea electrooxidation greatly limit their applications. This project is to solve its essence problem that the active NiOOH component is difficult to generate and is vulnerable to poisoning deactivation. With the aid of in-situ electrochemical method such as in-situ FTIR, the poison species is verified. Then transition metal carbides (TMCs) would be introduced to modulate the d-band density of Ni and correspondingly the binding energy on the surface of the poison species. Through studying the mechanisms of how the electronic structures of different types TMCs affect the Ni electro-negativity, the Ni outer electron transition would be modified to strengthen the active component of NiOOH. On the other hand, different types of the interaction of TMCs with Ni may weaken the adsorption strength of poison species on the catalyst surface, potentially improving the stability of the catalyst. By means of quantum chemistry calculation combined with a variety of characterization testing methods, the control rules of TMCs species characteristics on d-band density of Ni, and surface adsorption of poisoning species are explored. Furthermore, the reinforcement mechanisms of the urea TMCs electrooxidation NiOOH formation and stability of active components are revealed. Moreover, the structure-activity relationship between the interaction of Ni and TMCs on the surface electronic structure of Ni-based catalysts and the electrooxidation activity and stability of urea are clarified. This proposal is expected to provide scientific basis for the rational design of efficient and stable Ni/TMCs catalysts for urea electrooxidation.