Highly Productive Electrosynthesis of Ammonia by Admolecule-Targeting Single Ag Sites

Ying Chen; Ruijie Guo; Xianyun Peng; Xiaoqian Wang; Xijun Liu; Junqiang Ren; Jia He; Longchao Zhuo; Jiaqiang Sun; Yifan Liu; Yuen Wu; Jun Luo

doi:10.1021/acsnano.0c01340

Highly Productive Electrosynthesis of Ammonia by Admolecule-Targeting Single Ag Sites

ACS Nano. 2020 Jun 23;14(6):6938-6946. doi: 10.1021/acsnano.0c01340. Epub 2020 Jun 10.

Authors

Ying Chen¹, Ruijie Guo¹, Xianyun Peng¹, Xiaoqian Wang², Xijun Liu¹, Junqiang Ren³, Jia He¹, Longchao Zhuo⁴, Jiaqiang Sun⁵, Yifan Liu⁶, Yuen Wu², Jun Luo¹

Affiliations

¹ Center for Electron Microscopy and Tianjin Key Lab of Advanced Functional Porous Materials, Institute for New Energy Materials & Low-Carbon Technologies, School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384, China.
² School of Chemistry and Materials Science, iChEM, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei National Laboratory for Physical Sciences at the Microscale, Hefei 230026, China.
³ State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China.
⁴ School of Materials Science and Engineering, Xi'an University of Technology, Xi'an 710048, China.
⁵ State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China.
⁶ College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.

PMID: 32510924
DOI: 10.1021/acsnano.0c01340

Abstract

The ambient electrocatalytic N₂ reduction reaction (NRR) is a promising alternative to the Haber-Bosch process for producing NH₃. However, a guideless search for single-atom-based and other electrocatalysts cannot promote the NH₃ yield rates by NRR efficiently. Herein, our first-principles calculations reveal that the successive emergence of vertical end-on *N₂ and oblique end-on *NNH admolecules on single metal sites is key to high-performance NRR. By targeting the admolecules, single Ag sites with the Ag-N₄ coordination are found and synthesized massively. They exhibit a record-high NH₃ yield rate (270.9 μg h^-1 mg_cat.^-1 or 69.4 mg h^-1 mg_Ag^-1) and a desirable Faradaic efficiency (21.9%) in HCl aqueous solution under ambient conditions. The generation rate of NH₃ is stable during 20 consecutive reaction cycles, and the reduction current density is almost constant for 60 h. This work provides an effective targeting-design principle to purposefully synthesize active and durable single-atom-based NRR electrocatalysts.

Keywords: admolecule-targeting; ambient conditions; electrocatalysis; nitrogen fixation; single Ag sites.