Boosting CH₃OH Production in Electrocatalytic CO₂ Reduction over Partially Oxidized 5 nm Cobalt Nanoparticles Dispersed on Single-Layer Nitrogen-Doped Graphene

Abstract

Herein, we successfully synthesized partially oxidized 5 nm cobalt nanoparticles dispersed on a single-layer nitrogen-doped graphene (SL-NG) (denoted as PO-5 nm Co/SL-NG) catalyst by a unique and simple one-pot synthesis strategy, which was efficiently applied for highly selective electrocatalytic reduction of carbon dioxide to methanol in 0.1 mol dm–3 aqueous NaHCO3 medium under mild conditions, reaching the maximum faradaic efficiency (FE) of 71.4% for methanol at −0.90 V versus saturated calomel electrode (SCE), possessing a strong electrocatalytic current density of 4 mA cm–2 and a high yield of 1.10 mmol dm–3 h–1, and the corresponding overpotential is as low as 280 mV. Moreover, at −1.0 V versus SCE, a high current density of 10 mA cm–2 can be obtained, and the FE for methanol still remains 23.2%. Notably, the proposed catalyst exhibits prominent stability after 10 h electroreduction of CO2, and the morphology, particle size, structure, and element contents of the catalyst almost remain stable. This work first provides an advanced PO-5 nm Co/SL-NG for selective electroreduction of carbon dioxide into methanol, which simultaneously possesses the merits of high current density, low overpotential, high selectivity, superior FE, and good stability, outperforming most reported electrocatalysts.