Guo Xiaotian, Yu Jidong, Ren Shijie, Gao Rui-Ting, Wu Limin, Wang Lei
College of Chemistry and Chemical Engineering, College of Energy Material and Chemistry, Inner Mongolia University, Hohhot 010021, China.
Department of Materials Science and State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai 200433, China.
ACS Nano. 2024 Sep 3;18(35):24252-24261. doi: 10.1021/acsnano.4c05772. Epub 2024 Aug 21.
Electrochemical nitrate reduction reaction (NORR) is a promising low-carbon and environmentally friendly approach for the production of ammonia (NH). Herein, we develop a high-temperature quenched copper (Cu) catalyst with the aim of inducing nonequilibrium phase transformation, revealing the multiple defects (distortion, dislocations, vacancies, etc.) presented in Cu, which lead to low overpotential for NORR and high efficiency for NH production. Further loading a low content of iridium (Ir) species on the Cu surface improves the reactivity and ammonia selectivity. The resultant CuIr electrode exhibits a Faradaic efficiency of 93% and a record yield of 6.01 mmol h cm at -0.22 V exceeding those of state-of-the-art NORR catalysts. Detailed investigations have demonstrated that the synergistic effect between multiple defects and Ir decoration effectively regulate the d-band center of copper, change the adsorption state of the catalyst surface, and promote the adsorption and reduction of intermediates and reactants. The strong H* adsorption ability of the Ir element provides more active hydrogen for the generation of ammonia, promoting the reduction of nitrate to NH.
电化学硝酸盐还原反应（NORR）是一种很有前景的低碳环保制氨（NH₃）方法。在此，我们开发了一种高温淬火铜（Cu）催化剂，旨在引发非平衡相变，揭示Cu中存在的多种缺陷（畸变、位错、空位等），这些缺陷导致NORR的过电位较低且制氨效率较高。进一步在Cu表面负载低含量的铱（Ir）物种可提高反应活性和氨选择性。所得的CuIr电极在-0.22 V时表现出93%的法拉第效率和6.01 mmol h⁻¹ cm⁻²的创纪录产率，超过了目前最先进的NORR催化剂。详细研究表明，多种缺陷与Ir修饰之间的协同效应有效地调节了铜的d带中心，改变了催化剂表面的吸附状态，并促进了中间体和反应物的吸附与还原。Ir元素较强的H*吸附能力为氨的生成提供了更多活性氢，促进了硝酸盐向NH₃的还原。
