Ambient NH3 synthesis via electrochemical reduction of N2 over cubic sub-micron SnO2 particles

Abstract

Electrochemical N₂-to-NH₃ fixation under ambient conditions is emerging as a promising alternative to the energy-intensive and CO₂-emitting Haber–Bosch process. However, this process involves difficulty in N₂ activation, underlining the demand of electrocatalysts for the N₂ reduction reaction (NRR). In this work, cubic sub-micron SnO₂ particles on carbon cloth (SnO₂/CC) are proposed as an efficient NRR electrocatalyst for ambient N₂ conversion to NH₃ with excellent selectivity. Electrochemical tests reveal that SnO₂/CC attains a large NH₃ yield of 1.47 × 10⁻¹⁰ mol s⁻¹ cm⁻² at −0.8 V vs. reversible hydrogen electrode (RHE) and a high Faradaic efficiency of 2.17% at −0.7 V vs. RHE in 0.1 M Na₂SO₄, outperforming most reported aqueous-based NRR electrocatalysts. Notably, it also shows strong electrochemical stability.