Fan Zhenhai, Cao Chunmei, Yang Xingchuan, Yuan Wenchuang, Qin Feiyang, Hu Yating, Sun Xiaobo, Liu Guoji, Tian Yun, Xu Li
School of Chemical Engineering, Zhengzhou University, Zhengzhou, 450001, P. R. China.
Angew Chem Int Ed Engl. 2024 Oct 24;63(44):e202410356. doi: 10.1002/anie.202410356. Epub 2024 Sep 23.
Electrocatalytic nitrate (NO ) reduction to ammonia (NRA) offers a promising pathway for ammonia synthesis. The interfacial electronic interactions (IEIs) can regulate the physicochemical capabilities of catalysts in electrochemical applications, while the impact of IEIs on electrocatalytic NRA remains largely unexplored in current literature. In this study, the high-efficiency electrode Ag-modified CoO (AgCo/CC) is prepared for NRA in neutral media, exhibiting an impressive nitrate conversion rate of 96.86 %, ammonia Faradaic efficiency of 96.11 %, and ammonia selectivity of ~100 %. Notably, the intrinsic activity of AgCo/CC is ~81 times that of Ag nanoparticles (Ag/CC). Multiple characterizations and theoretical computations confirm the presence of IEIs between Ag and CoO, which stabilize the CoO octahedrons within CoO and significantly promote the adsorption of reactants (NO ) as well as intermediates (NO and NO), while suppressing the Heyrovsky step, thereby improving nitrate electroreduction efficiency. Furthermore, our findings reveal a synergistic effect between different active sites that enables tandem catalysis for NRA: NO reduction to NO predominantly occurs at Ag sites while NO tends to hydrogenate to ammonia at Co sites. This study offers valuable insights for the development of high-performance NRA electrocatalysts.
电催化硝酸盐（NO₃⁻）还原制氨（NRA）为氨合成提供了一条很有前景的途径。界面电子相互作用（IEIs）可以调节催化剂在电化学应用中的物理化学性能，而IEIs对电催化NRA的影响在当前文献中仍基本未被探索。在本研究中，制备了用于中性介质中NRA的高效电极Ag修饰的CoO（AgCo/CC），其硝酸盐转化率达96.86%，氨法拉第效率达96.11%，氨选择性约为100%，令人印象深刻。值得注意的是，AgCo/CC的本征活性约为Ag纳米颗粒（Ag/CC）的81倍。多种表征和理论计算证实了Ag与CoO之间存在IEIs，这使CoO中的CoO八面体得以稳定，并显著促进反应物（NO₃⁻）以及中间体（NO₂⁻和NO）的吸附，同时抑制海洛夫斯基步骤，从而提高硝酸盐电还原效率。此外，我们的研究结果揭示了不同活性位点之间的协同效应，这种协同效应能够实现NRA的串联催化：NO₃⁻还原为NO₂⁻主要发生在Ag位点，而NO₂⁻倾向于在Co位点氢化为氨。本研究为高性能NRA电催化剂的开发提供了有价值的见解。
