Modulating the Energetics of C–H Bond Activation in Methane by Utilizing Metalated Porphyrinic Metal–Organic Frameworks

Abstract

In recent years, much effort has been directed toward utilizing metal–organic frameworks (MOFs) for activating C–H bonds of light alkanes. The energy demanding steps involved in the catalytic pathway are the formation of metal-oxo species and the subsequent cleavage of the C–H bonds of alkanes. With the intention of exploring the tunability of the activation barriers involved in the catalytic pathway of methane hydroxylation, we have employed density functional theory to model metalated porphyrinic MOFs (MOF-525(M)). We find that the heavier congeners down a particular group have high exothermic oxo-formation enthalpies ΔH O and hence are associated with low N2O activation barriers. Independent analyses of activation barriers and structure–activity relationship leads to the conclusion that MOF-525(Ru) and MOF-525(Ir) can act as an effective catalysts for methane hydroxylation. Hence, ΔH O has been found to act as a guide, in the first place, in choosing the optimum catalyst for methane hydroxylation from a large set of available systems.

Graphene-Supported Single-Atom Ni as High-Performance Catalyst for Direct Methane-to-Methanol Conversion

“…In the future, it is worth exploring single Ni-atom anchored in other substrates, such as N-, O-, or S-doped graphene ,,,, and porphyrin-based covalent organic frameworks, ,− or extending the single Ni-atom to metal clusters, ,− which may provide multiple active sites. It would also be interesting to investigate whether the activity trend of Ni, Pd, and Pt found in this study is general for aforementioned systems as well as for transition metals in other groups.…”

Rational Design of the Catalysts for the Direct Conversion of Methane to Methanol Based on a Descriptor Approach

“…Thus, developing activity descriptors with accessible properties of catalytic systems to understand the activity of active sites is critical; these descriptors are based on scaling relationships [50,51]. With suitable activity descriptors, we can directly judge whether catalysts have the capacity to activate methane and should be examined further by experimental and complete reaction path calculations [52,53].…”

“…Recently, activity descriptors have been successfully applied to screen catalysts based on zeolites [76], 2D materials [75], and MOFs [53] for direct methane-to-methanol conversion. In this section, we mainly take 2D materials as examples, which have a rich adjustment space, and use activity descriptors to reveal the effect of different regulation approaches on the activity of direct methanol production from methane and screen optimal active sites.…”