Two-dimensional atomically thin hexagonal boron nitride (h-BN) monolayer has attracted considerable research interest. Given the tremendous progress in the synthesis of h-BN monolayers on transition metals and their potential as electrocatalysts, we investigate the electrocatalytic activities of h-BN/Ni, h-BN/Co, and h-BN/Cu for CO2 reduction by first-principles density functional theory (DFT). We find that with the h-BN monolayer on the metal, electrons transfer from the metal to the interface and accumulate under the B atoms. By calculating the binding energies of three key intermediates (H, HCOO, and COOH) for hydrogen evolution and CO2 reduction, we find that H binding on the metal can be significantly weakened by the h-BN monolayer, preventing the hydrogen-evolution reaction (HER). But the binding strength of HCOO is strong on both the metal and h-BN/metal, especially for Ni and Co, promoting the CO2 reduction channel. Based on the free-energy diagrams, we predict that h-BN/Ni and h-BN/Co can be very good electrocatalysts for CO2 reduction to HCOOH while the competitive HER channel is filtered out by the surface h-BN monolayer. Our study opens a new way for selective electroreduction of CO2 via the interface engineering of the h-BN/metal system.

Surface engineering of earth-abundant transition metals by boron nitride for selective reduction of CO2

255th National Meeting (2018)

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