Electronic Modulation by C60-Fullerene Inhibits Methanol Dehydrogenation on Vanadium Clusters.

Methanol is an attractive hydrogen carrier, and understanding its activation and dehydrogenation by supported metal catalysts is vital for realizing the methanol economy proposed by Nobel Prize laureate Olah. In this work, we investigate the reactions of C60-supported cationic vanadium clusters, C60Vn+ (n = 1-10), toward methanol and contrast the results with those of bare Vn+ clusters. While bare Vn+ clusters efficiently catalyze methanol dehydrogenation to release H2, C60Vn+ clusters exhibit striking inertness, yielding only methanol adsorption products. Kinetic modeling and RRKM analysis suggest that this inertness cannot be attributed simply to intramolecular redistribution of adsorption energy but mainly stems from electronic modification of the vanadium clusters by the C60-support. Density functional theory calculations for n = 7 identify formation and release of the first H2 molecule as the rate-determining step, with energy demand of 208 kJ/mol for C60V7+ compared to 131 kJ/mol for V7+. Charge analysis and energy decomposition analysis show that C60 induces substantial electron transfer from vanadium to the fullerene cage, rendering the metal sites more electron-deficient and thereby strengthening metal-hydrogen interactions through enhanced orbital interactions in key intermediates. These results demonstrate that C60 is not an inert scaffold but an active electronic modulator that can reshape the electronic structures and thus the reactivity of the supported metal catalysts, offering new insights into the roles of fullerenes in catalysis.