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.