Highly active metal-free hetero-nanotube catalysts for hydrogen evolution reaction.

The development of low-cost and high-efficiency catalysts for hydrogen evolution reaction is of importance in hydrogen production. In this study, we investigate H adsorption at the interfaces of C/BN hetero-nanotubes using first-principles density functional theory calculations. Substantial charge redistributions associated with states near the Fermi level occur at the interfaces. More importantly, such electronic modification can enhance the hydrogen adsorption at the interfacial atoms. As a result, the adsorption free energies ΔGH* of H for the interfaces range from -0.26 to 0.30 eV, depending on H coverage. These values are much closer to zero than those for the basal plane, suggesting that the interfaces can be active sites for hydrogen evolution reaction. The interfacial adsorption sites show a distinctive hybridization between the H s and C p orbitals, which accounts for the enhanced H adsorption at the interfaces. These findings have important implications for hydrogen energy applications.