Activating the hydrogen evolution reaction in low-dimensional carbon by partial hydrogenation: Role of the hybrid sp2-sp3 orbital interface

Developing highly efficient catalyst for the hydrogen evolution reaction (HER) and understanding their mechanism is crucial for establishing the hydrogen economy. Carbon-based materials are particularly attractive as HER catalysts because of their abundance and morphological variety. Herein, using density functional theory (DFT) calculations, we propose for the first time a virtual interface consisting of sp² and sp³ orbitals of carbon, for activating the intrinsically inert low-dimensional carbon toward the HER. This hybrid orbital interface is generated by pre-adsorbed hydrogen introduced by the partial hydrogenation of these low-dimensional carbon materials (C₆₀, carbon nanotubes and graphene). The pre-adsorbed hydrogen can activate adjacent carbon atoms to become active sites for the HER. The best performance among these sites is comparable to that of the commercial Pt/C catalyst. Given that the partial hydrogenation of low-dimensional carbon has been experimentally realized, our work provides a simple yet novel concept for HER catalyst design.