NiFe-CN catalysts derived from the solid-phase exfoliation of NiFe-layered double hydroxide for CO2 electroreduction

Abstract

The development of efficient carbon dioxide reduction reaction (CO₂RR) catalysts is one of the practical solutions to the current environmental problems. Usually, metal-doped catalysts are used for the CO₂RR, but the metal elements can easily aggregate, resulting in a reduction in the catalytic performance. In this study, NiFe-LDH was exfoliated to single layer by a solid-phase exfoliation strategy, wherein Ni and Fe were doped on the char material owing to the pyrolysis of the solid-phase exfoliation agent, and the NiFe-CN catalyst with a gauzy and porous structure was obtained. The catalyst possessed excellent catalytic performance; particularly, when the mass fraction of NiFe-LDH was 1 wt%, the prepared catalyst (NiFe-CN-1) showed a faradaic efficiency of 93.5% for the reduction of CO₂ to CO at −0.8 V (vs. reversible hydrogen electrode (RHE)) with a CO current density of 10.4 mA cm⁻², which was due to the sufficient exposure of active sites and efficient proton transfer channels of NiFe-CN. This strategy provides a new idea to easily mass produce CO₂RR electrocatalysts in an environmentally benign way.