Understanding the CH 4 Conversion over Metal Dimers from First Principles.

Inspired by the advantages of bi-atom catalysts and recent exciting progresses of nanozymes, by means of density functional theory (DFT) computations, we explored the potential of metal dimers embedded in phthalocyanine monolayers (M 2 -Pc), which mimics the binuclear centers of methane monooxygenase, as catalysts for methane conversion using H 2 O 2 as an oxidant. In total, 26 transition metal (from group IB to VIIIB) and four main group metal (M = Al, Ga, Sn and Bi) dimers were considered, and two methane conversion routes, namely *O-assisted and *OH-assisted mechanisms were systematically studied. The results show that methane conversion proceeds via an *OH-assisted mechanism on the Ti 2 -Pc, Zr 2 -Pc and Ta 2 -Pc, a combination of *O- and *OH-assisted mechanism on the surface of Sc 2 -Pc, respectively. Our theoretical work may provide impetus to developing new catalysts for methane conversion and help stimulate further studies on metal dimer catalysts for other catalytic reactions.