A New Class of Molecular Electrocatalysts for Hydrogen Evolution: Catalytic Activity of M3N@C2n (2n = 68, 78, and 80) Fullerenes

Abstract

The electrocatalytic properties of some endohedral fullerenes for hydrogen evolution reactions (HER) were recently predicted by DFT calculations. Nonetheless, the experimental catalytic performance under realistic electrochemical environments of these 0D-nanomaterials have not been explored. Here, for the first time, we disclose the HER electrocatalytic behavior of seven M₃[email protected]n (2n = 68, 78, and 80) fullerenes (Gd₃[email protected]I_h(7)-C₈₀, Y₃[email protected]I_h(7)-C₈₀, Lu₃[email protected]I_h(7)-C₈₀, Sc₃[email protected]I_h(7)-C₈₀, Sc₃[email protected]D_5h(6)-C₈₀, Sc₃[email protected]D_3h(5)-C₇₈, and Sc₃[email protected]D₃(6140)-C₆₈) using a combination of experimental and theoretical techniques. The non-IPR Sc₃[email protected]D₃(6140)-C₆₈ compound exhibited the best catalytic performance toward the generation of molecular hydrogen, exhibiting an onset potential of −38 mV vs RHE, a very high mass activity of 1.75 A·mg^–1 at −0.4 V vs RHE, and an excellent electrochemical stability, retaining 96% of the initial current after 24 h. The superior performance was explained on the basis of the fused pentagon rings, which represent a new and promising HER catalytic motif.