J. Am. Chem. Soc. - Selective Mass Accumulation at the Metal-Polymer Bridging Interface for Efficient Nitrate Electroreduction to Ammonia and Zn-Nitrate Batteries

Guojie Chao, Wei Zong*, Jiexin Zhu, Haifeng Wang, Kaibin Chu, Hele Guo, Jian Wang, Yuhang Dai, Xuan Gao, Longxiang Liu, Fei Guo, Ivan P. Parkin, Wei Luo, Paul R. Shearing, Longsheng Zhang*, Guanjie He*, Tianxi Liu*

J. Am. Chem. Soc. 2025, DOI: 10.1021/jacs.5c00400

The electrochemical conversion of nitrate (NO3–), a common nitrogen source in industrial wastewater and contaminated groundwater, into ammonia (NH3), signifies an approach to wastewater treatment and NH3 production. Nevertheless, its selectivity and activity at low NO3– concentrations and industrial current densities are constrained by limited mass transfer around the electrode. Here, we report a metal–polymer bridging interface constructed by anchoring Cu/Cu2O nanoparticles onto a two-dimensional (2D) Cu-based benzene dicarboxylate (CuBDC) coordination polymer via in situ electroreduction (denoted as E-CuBDC). This interface weakens the electrostatic repulsion and regulates the distribution/migration of NO3– and H2O, creating a Janus NO3–-rich and H2O-poor domain near the catalyst surface. Operando characterizations and theoretical simulations indicate that the metal–polymer bridging interface selectively accumulates NO3– and reduces the energy barrier toward the reduction of *NH2OH to *NH2, overcoming the mass transfer limitations at a low NO3– concentration. E-CuBDC exhibits a high Faradaic efficiency (FE) of over 90% across wide NO3– concentrations (7.1–100 mM NO3–) and high applied voltages. Additionally, it achieved stable NH3 production over 100 h at ampere-level current densities. When applied in a Zn–NO3– system, this newly developed E-CuBDC catalyst demonstrates an outstanding power density and FE for NH3 production, showcasing its great potential for large-scale electrochemical conversion and storage systems. This study presents a generalizable strategy for constructing metal–polymer interfaces to regulate interfacial mass transport.

Link: https://doi.org/10.1021/jacs.5c00400