Endohedral metallofullerenes (M@C60) as efficient catalysts for highly active hydrogen evolution reaction

Abstract

The cage structure of C60 fullerenes with encapsulated metal atoms, i.e. endohedral fullerenes (M@C60) possess unique electronic properties with novel applications. By using density functional theory (DFT), we for the first time predict endohedral M@C60 (M=Na, K, Rb, Cs, Sc, Ti, Mn, Fe) fullerenes from 20 possible candidates as promising high performance hydrogen evolution reaction (HER) catalysts. For the pristine C60, the Gibbs free energy is too positive to prevent the adsorption of H-atoms on surface carbon atoms. However, when a metal atom is embedded in the C60 cage, the H-atom binding free energy on M@C60 can be optimized to ideal value for HER (ΔGH=0). The catalytic active site is non-metal C-atom and the HER performance of M@C60 are even better than those of the state-of-the-art Pt and MoS2 catalysts. The excellent catalytic activities are attributed to the charge transfer between the metal atom and C60 cage. Since the endohedral fullerenes can be easily realized in experiment, our findings highlight a new class of low-cost and efficient HER catalyst for experimental validation studies toward hydrogen production.