Ni3N nanoparticles on porous nitrogen-doped carbon nanorods for nitrate electroreduction

Abstract

Electrocatalytic nitrate reduction into recyclable ammonium under mild conditions provides an efficient and clean ammonium production strategy and remediation of nitrate-containing wastewater. In this work, we successfully synthesize the Ni3N nanoparticles anchored on nitrogen-doped carbon (Ni3N/N-C) nanohybrids through simple calcination and acid etching procedures using Ni-dimethylglyoxime complex (Ni-DMG) nanorods as raw material. Physical characterizations confirm that as-synthesized Ni3N/N-C nanohybrids have the high specific surface area of 665.7 m2 g−1 and the ultrafine Ni3N nanoparticles (5.3 nm) are dispersed uniformly on the surface of porous nitrogen-doped carbon nanorods. The electrochemical experiments indicate that the combination of nitrogen-doped carbon can greatly improve electroactivity of Ni3N nanoparticles for nitrate reduction reaction. Consequently, Ni3N/N-C nanohybrids possess high selectivity for ammonium production (89.5%) and high yield rate of ammonium (9.185 mmol h−1 mgNi3N−1) for nitrate electroreduction. Additionally, Ni3N/N-C nanohybrids also show excellent long-term stability due to their structural/chemical stability.