Issue

Vol. 19 (2027)

Interfacial Electronic Regulation in N-Doped Carbon-Encapsulated NiCo Alloy Enables High-Current Nitrate-to-Ammonia Electrosynthesis

https://doi.org/10.1007/s40820-026-02359-6
Qizhi Hu
State Key Laboratory of Materials‑Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 211816, People’s Republic of China
Siyu Zhu
School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
Biao Meng
State Key Laboratory of Materials‑Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 211816, People’s Republic of China
Mingdong Sun
State Key Laboratory of Materials‑Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 211816, People’s Republic of China
Mingzhen Wang
State Key Laboratory of Materials‑Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 211816, People’s Republic of China
Xiaoling Liu
State Key Laboratory of Materials‑Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 211816, People’s Republic of China
Shibo Xi
Institute of Sustainability for Chemicals, Energy and Environment (ISCE2), Agency for Science, Technology and Research (A*STAR), 1 Pesek Road Jurong Island, Singapore 627833, Singapore
Xiao Chi
Department of Physics, National University of Singapore, Singapore 117576, Singapore
Xiaojiang Yu
Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603, Singapore
Jing Wu
State Key Laboratory of Materials‑Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 211816, People’s Republic of China
Yu Zhou
State Key Laboratory of Materials‑Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 211816, People’s Republic of China
Yizhong Huang
School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
Jun Wang
State Key Laboratory of Materials‑Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 211816, People’s Republic of China

Corresponding Author: Jun Wang

junwang@njtech.edu.cn

Nano-Micro Letters, Vol. 19 (2027), Article Number: 58

Abstract

Electrochemical nitrate reduction (NO3−RR) offers a route to couple wastewater remediation with green ammonia (NH3) synthesis, but remains kinetically and mechanistically challenging under high-current-density operation. Herein, an N-doped carbon-encapsulated NiCo alloy catalyst (NiCo@NC) is derived from a NiCo-ZB precursor supported on conductive carbon black. The cathodic NO3−RR over NiCo@NC achieves an NH3 yield rate of 187 mol h−1 gcat−1 with 95% Faradaic efficiency (FE) at −0.6 VRHE in an H-type cell and sustains ~92% FE at 2.0 A cm−2 under a cell voltage of 3.3 V in a membrane–electrode assembly. Pairing this cathodic NO3−RR with anodic methanol oxidation to formate enables simultaneous NH3 and formate production at 2.1 A cm−2 under a cell voltage of 2.8 V, while maintaining NH3 and formate FEs above 90% and 96%, respectively. In situ Fourier transform infrared and operando X-ray absorption fine structure spectra reveal preferential *NO stabilization and reversible Co valence/coordination, while theoretical calculations disclose interfacial charge polarization between NiCo alloy core and N-doped carbon shell, fabricating dual sites, comprising electron-deficient graphitic carbon and electron-rich pyridinic-N domains, that accelerate water dissociation/proton supply and lower the barrier of the rate-determining *NO → *NOH step. These insights establish alloy@NC interface regulation as a general strategy for high-rate NO3−RR.


Highlights:
1 N-doped carbon-encapsulated NiCo alloy enables high-rate nitrate-to-ammonia electrosynthesis.
2 Alloy–carbon interfacial polarization creates dual sites for water activation and intermediate hydrogenation.
3 Ampere-level NH3 synthesis is achieved in membrane–electrode assembly with efficient paired NH3/formate co-electrolysis.

Keywords

Ammonia electrosynthesis Electrochemical nitrate reduction Alloy catalysts Heterogeneous catalysis Carbon materials
Hu, Qizhi, Siyu Zhu, Biao Meng, Mingdong Sun, Mingzhen Wang, Xiaoling Liu, Shibo Xi, Xiao Chi, Xiaojiang Yu, Jing Wu, Yu Zhou, Yizhong Huang, and Jun Wang. 2026. “Interfacial Electronic Regulation in N-Doped Carbon-Encapsulated NiCo Alloy Enables High-Current Nitrate-to-Ammonia Electrosynthesis”. Nano-Micro Letters 19 (November):58. https://doi.org/10.1007/s40820-026-02359-6.
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