Metal-free graphene/boron nitride heterointerface for CO2 reduction: Surface curvature controls catalytic activity and selectivity

Metal-free graphene/boron nitride heterointerface for CO2 reduction: Surface curvature controls catalytic activity and selectivity

Searching environmentally friendly and low-cost catalysts for CO2 reduction is critical for the development of sustainable energy and environmental technologies. In this work, we report a novel heterointerface between graphene and BN nanotubes or nanoribbons as efficient catalysts for CO2 reduction with high activity and selectivity. The active sites are found to be at the C-N interfaces of graphene-BN (G-BN) and their excellent catalytic performance is derived from the surface curvature effect. The density functional theory (DFT) results reveal that the most energy favorable pathway for the formation of CH3OH is * + CO2 → *COOH → *CO → *OCH → *OCH2 → *OCH3 → *CH3OH → * + CH3OH. And the formation of CH4 is through * + CO2 → *COOH → *CO → *OCH → *OCH2 → *OCH3 → *O + CH4 → *OH + CH4 → *H2O + CH4 pathway. Moreover, the calculated results further demonstrate that for the smaller index of G-BN nanotubes, such as G-BN (3), the formation of CH3OH product is much easier than the *O intermediate and CH4 molecule due to the lower free energy change. However, for the higher indexed G-BN nanotubes, after forming *OCH3 intermediate, the generation of *O and CH4 molecule is more feasible, particularly for G-BN (9), and the calculated limiting potential is only −0.42 V, which is higher than the best Cu-based materials, like −0.93 V on Cu(111), and −0.74 V on Cu (211). This metal free heterostructure is confirmed to facilitate CO2 conversion with high activity and selectivity, demonstrating a great potential as a new type of catalyst for CO2 reduction.