Highly reactive Cu-Pt bimetallic 3D-electrocatalyst for selective nitrate reduction to ammonia

Abstract

Identifying electrocatalytic materials that generate fossil-free ammonia through N-recycling from polluted water sources is required. Bimetallic Cu-Pt foam electrodes were synthesized to enhance electrochemical reduction of nitrate (ERN) by the introduction of bimetallic catalytic sites. Electrodes were benchmarked against Cu foam using engineering figures of merit. Cu-Pt (180 s) electrode achieved 94% conversion of NO3--N in 120 min yielding 194.4 mg NH3- N L−1 gcat−1, with a selectivity towards ammonia (SNH3) of 84% and an electrical energy per order decrease by ~70% respect pristine Cu foam. Bimetallic electrodes with low Pt loadings (<0.50 wt%) demonstrated that synergistic effects of Cu-Pt nanointerfaces enabled hybridized mechanisms of catalytic electrochemical and hydrogenation reduction processes. These encouraging outcomes emphasize the potential of Cu-Pt foam electrodes to treat contaminated water sources with nitrate, while allowing a sustainable decentralized ammonia recovery. Enriched water for crops irrigation can therefore be a prospect use for this added value product.