Metal-Free Boron Nitride Nanoribbon Catalysts for Electrochemical CO2 Reduction: Combining High Activity and Selectivity

Developing metal-free catalysts for reduction of CO 2 into energy-rich products is a popular yet very challenging topic. Using density functional theory calculations, we investigated the electrocatalytic performance of C-doped and line-defect (Ld)-embedded boron nitride nanoribbons (BNNRs) for CO 2 reduction reaction (CRR). Because of the presence of bare edge B atoms neighboring to C dopant and C 2 dimer as active sites, defective BNNRs exhibit high CRR catalytic activity and selectivity. The Ld-embedded BNNR structures with C 2 dimer can not only convert CO 2 into CO with very low overpotential of −0.5 V versus reversible hydrogen electrode but also ensure high selectivity in deactivating the hydrogenation channel of the desorbed CO to CH 4 . The C-doped zigzag and armchair BNNRs bind strongly to the CO intermediate and thus promote the selective conversion of CO 2 to CH 4, with the lower energy cost on the armchair ribbon than the zigzag one. The presence of edge B atoms and C dopant as dual active sites in BNNRs enables effective couplings between *CH 2 and CO intermediates, leading to the formation of C 2 products including C 2 H 4 and C 2 H 5 OH, with a high selectivity for C 2 H 5 OH. Importantly, unwanted hydrogen evolution reaction is suppressed during CRR catalyzed by these BNNR-based configurations. Overall, the present findings highlight a promising new class of low-cost, metal-free electrocatalysts combining high CRR activity and selectivity.