Enhanced Electrochemical Nitrate Reduction to Ammonia with Nanostructured Mo2C on Carbon Nanotube-Reduced Graphene Oxide Hybrid Support

Abstract

The electrochemical nitrate reduction reaction (NO3−RR) is emerging as a promising method for ammonia production under ambient conditions while simultaneously addressing nitrate pollution. Due to the complexity of NO3−RR, which involves multi-electron/proton transfer and competes with the hydrogen evolution reaction (HER), the development of efficient electrocatalysts with high activity and stability is crucial. In this study, we report the use of Mo2C nanoparticles homogeneously dispersed on a carbon nanotube-reduced graphene oxide hybrid support (Mo2C/CNT-RGO) as an effective electrocatalyst for NO3−RR. The three-dimensional CNT-RGO hybrid provides a large surface area for electrolyte contact, enhanced electrical conductivity, and prevents the aggregation of Mo2C nanoparticles. Consequently, the Mo2C/CNT-RGO electrocatalyst demonstrated high NO3−RR performance, achieving a maximum NH3 production rate of 5.23 mg h−1 cm−2 with a Faradaic efficiency of 95.9%. The Mo2C/CNT-RGO also exhibited excellent long-term stability during consecutive cycling tests. This work presents a promising strategy for developing high-performance and durable NO3−RR electrocatalysts.