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 at the potential of −0.40 V (vs. RHE) and high faradaic efficiency (FE) of 10.34% at the potential of −0.35 V (vs. RHE) in 0.1 M Na2SO4 electrolyte. The combination of BN QDs and CoP significantlyinhibitedcompetitiveHERprocess. 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.