Glucose oxidation assisted ammonia production via electrochemical dinitrogen reduction over CoWO4

Abstract

The electrochemical N₂ reduction reaction (NRR) at ambient temperature and pressure is an environmental friendly method for N₂ to NH₃ conversion. Nevertheless, the overall energy input can be reduced by replacing the sluggish oxygen evolution reaction (OER) with the more favourable glucose oxidation reaction (GOR) at the counter electrode. Designing an efficient, bifunctional and cost-effective catalyst for NRR and GOR exhibiting impressive performance is crucial yet challenging. Here, we report a facile one step hydrothermal approach for the synthesis of cobalt tungstate (CoWO₄) with an urchin-like morphology by simple variation of reaction time for application in glucose assisted NRR. A morphology dependent activity was revealed by CoWO₄ (12 h) with a high NH₃ yield rate of 667.86 μg h⁻¹ mg_cat⁻¹ and faradaic Efficiency (F.E.) of 22.34% at −0.35 V vs. reversible hydrogen electrode (RHE) with a TOF (turn over frequency) of 0.67 h⁻¹ under alkaline conditions. Notably, the ammonia production was enhanced at 0.27 V lower potential in the presence of glucose under full cell conditions.