He Zhifeng, Cui Xin, Lei Guangping, Liu Zeyi, Yang Xiaoyang, Liu Yifu, Wan Jiafeng, Ma Fangwei
Key Laboratory of Chemical Engineering Processes&Technology for High-efficiency Conversion (College of Heilongjiang Province), School of Chemistry and Material Science, Heilongjiang University, Harbin, 150080, China.
School of Energy and Power Engineering North University of China, Taiyuan, 030051, China.
Dalton Trans. 2023 Feb 28;52(9):2887-2897. doi: 10.1039/d2dt03275a.
Molybdenum (Mo) is one of the most important constituent elements in natural nitrogenase and theoretical calculation results show that Mo-based materials can be used as potential NRR electrocatalysts. The design of advanced catalysts with a special structure is very essential for promoting the development of electrocatalytic N into NH. In this paper, Fe-doped MoO/C heterostructured nanoparticles with rich oxygen vacancies (Vo) are designed and they exhibit highly efficient catalytic activity for artificial N fixation in neutral electrolytes under ambient conditions. The influence of the atomic ratio of the Fe source to the Mo source and the NaBH ethanol solution treatment on the structure and electrocatalytic performance are systematically investigated. The Vo-Fe-MoO/C (1 : 50) catalyst with rich oxygen vacancies shows a satisfactory electrocatalytic N reduction reaction (e-NRR) activity in 0.1 M NaSO with a high ammonia yield rate of 15.87 ± 0.3 μg h mg at -0.5 V the reversible hydrogen electrode ( the RHE) and a FE of 13.4% at -0.3 V ( the RHE). According to the results of DFT calculations, the active center of the electro-catalytic nitrogen reduction reaction is the molybdenum atom between the iron atom and the O vacancy. Oxygen vacancies can not only reduce the energy barrier of the RDS but also facilitate the desorption of ammonia and the first step hydrogenation of nitrogen. The doping of Fe will change the electronic state of the Mo atom in MoO.
钼（Mo）是天然固氮酶中最重要的组成元素之一，理论计算结果表明，钼基材料可作为潜在的氮还原反应（NRR）电催化剂。设计具有特殊结构的先进催化剂对于促进电催化氮气转化为氨的发展至关重要。本文设计了具有丰富氧空位（Vo）的铁掺杂MoO/C异质结构纳米颗粒，它们在环境条件下的中性电解质中对人工固氮表现出高效的催化活性。系统研究了铁源与钼源的原子比以及硼氢化钠乙醇溶液处理对结构和电催化性能的影响。具有丰富氧空位的Vo-Fe-MoO/C（1∶50）催化剂在0.1 M NaSO中表现出令人满意的电催化氮还原反应（e-NRR）活性，在相对于可逆氢电极（RHE）为-0.5 V时氨产率高达15.87±0.3 μg h mg，在-0.3 V（RHE）时法拉第效率（FE）为13.4%。根据密度泛函理论（DFT）计算结果，电催化氮还原反应的活性中心是铁原子和氧空位之间的钼原子。氧空位不仅可以降低速率决定步骤（RDS）的能垒，还有利于氨的脱附和氮的第一步加氢。铁的掺杂会改变MoO中钼原子的电子态。
