In situ interface engineered Co/NC derived from ZIF-67 as an efficient electrocatalyst for nitrate reduction to ammonia

Electrocatalytic nitrate (NO3-) reduction to ammonia (NH3) is a promising alternative approach for simul-taneous NH3 green synthesis and NO3- contaminants removal. However, the complex eight-electron reac-tion requires catalysts with superb performance due to the low NH3 selectivity and yield. In this work, the Co nanoparticles decorated N-doped carbon (NC) by in situ interface engineering were prepared by deriv-ing ZIF-67 at 800 celcius (Co/NC-800) for the selective NH3 synthesis. This catalyst exhibits a remarkable per-formance and excellent cycle stability, achieving a great NH3 yield of 1352.5 lg h-1 mgcat-1 at-1.7 V vs Ag/ AgCl, with a high NH3 selectivity of up to 98.2 %, and a maximum Faradic efficiency of 81.2 % at-1.2 V vs Ag/AgCl. Moreover, DFT calculation results indicate that the interfacial effect between Co nanoparticle and NC could enhance electron transfer, and the composite Co/NC-800 shows a lower adsorption and conversion free energy, which promotes the production of ammonia.(c) 2023 Elsevier Inc. All rights reserved.