Boron Nitride Quantum Dots Coupled with Cop Nanosheet Arrays Grown on Carbon Cloth for Efficient Nitrogen Reduction Reaction

Abstract

As a promising alternative technology to the Haber-Bosch process for industrial-scale NH3 production, Electrochemical nitrogen reduction reaction (NRR) is considered a sustainable and environmentally-benign alternative N2-to-NH3 conversion. Although low-cost cobalt phosphide (CoP) is a potential efficient NRR electrocatalyst, the relatively low activation capability of the N≡N triple bond significantly limits the further improvement of the electrocatalytic activity. Herein, the boron nitride quantum dots (BN QDs) are densely assembled on the surfaces of CoP nanosheets array/carbon cloth (CC) to enhance the electrocatalytic NRR performance. The results demonstrate that the BN QDs@CoP/CC delivers a high NH3 yield rate of 5.39×10 -10 mol s-1cm-2 and high faradaic efficiency (FE) of 32.62% at the potential of -0.40 V (vs. RHE) in 0.1 M Na2SO4 electrolyte. Also, the BN QDs@CoP/CC shows good durability with a high yield rate of NH3 and FE within the recycling test 7 times. Density functional theory calculations reveal that the N2 molecules prefer to be adsorbed on the edge-B sites of BN QDs which provide additional abundant surface-active sites. More importantly, the electron enrichment on the edge-B atoms improves their electron-donating ability to activate stable N≡N bonds, for which the BN QDs@CoP/CC performs better NRR activity and selectivity.

Keywords: Nitrogen reduction reaction, Cobalt Phosphide, Boron Nitride, Quantum Dots