Promoting the OH cycle on an activated dynamic interface for electrocatalytic ammonia synthesis

Jiabao Lv; Ang Cao; Yunhao Zhong; Qingyang Lin; Xiaodong Li; Hao Bin Wu; Jianhua Yan; Angjian Wu

doi:10.1038/s41467-024-50988-5

Promoting the OH cycle on an activated dynamic interface for electrocatalytic ammonia synthesis

Nat Commun. 2024 Aug 6;15(1):6675. doi: 10.1038/s41467-024-50988-5.

Authors

Jiabao Lv^{1

2}, Ang Cao^{1

3}, Yunhao Zhong¹, Qingyang Lin¹, Xiaodong Li¹, Hao Bin Wu⁴, Jianhua Yan⁵, Angjian Wu^{6

7}

Affiliations

¹ State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, P. R. China.
² Baima Lake Laboratory, Hangzhou, P. R. China.
³ Department of Physics, Technical University of Denmark, Kongens Lyngby, Denmark.
⁴ State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, P. R. China. [email protected].
⁵ State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, P. R. China. [email protected].
⁶ State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, P. R. China. [email protected].
⁷ Baima Lake Laboratory, Hangzhou, P. R. China. [email protected].

Abstract

Renewable-driven electrocatalytic nitrate conversion offers a promising alternative to alleviate nitrate pollution and simultaneously harvest green ammonia. However, due to the complex proton-electron transfer processes, the reaction mechanism remains elusive, thereby limiting energy efficiency. Here, we adopt Ni(OH)₂ as a model catalyst to investigate the dynamic evolution of the reaction interface. A proposed OH cycle mechanism involves the formation of a locally OH-enriched microenvironment to promote the hydrogenation process, which is identified through in-situ spectroscopy and isotopic labelling. By further activating the dynamic state through the implementation of surface vacancies via plasma, we achieve a high Faradaic efficiency of almost 100%. The activated interface accelerates the OH cycle by enhancing dehydroxylation, water dissociation, and OH adsorption, thereby promoting nitrate electroreduction and inhibiting hydrogen evolution. We anticipate that rational activation of the dynamic interfacial state can facilitate electrocatalytic interface activity and improve reaction efficiency.