Conversion of Methane into Liquid Fuels—Bridging Thermal Catalysis with Electrocatalysis

Abstract

The direct partial oxidation of methane to methanol promises an energy‐efficient and environmental‐friendly utilization of natural gas. Unfortunately, current technologies confront a grand challenge in catalysis, particularly in the context of distributed sources. Research has been focused on the design of homogenous and heterogenous catalysts to improve the activation of methane under thermal and electrochemical conditions. However, the intrinsic relationship between thermal and electrochemical systems has not been exploited yet. This review intends to bridge the studies of thermal and electrochemical catalysts, in both homogenous and heterogenous systems, for methane activation from a mechanistic point of view. It is expected to provide a framework to rationalize the design of electrocatalysts beyond the state of art. First, methane activation systems reported previously are reviewed and classified into two basic mechanisms: dehydrogenation and deprotonation. Based on the mechanism types, activity and selectivity descriptors are defined to understand the performance of current catalysts and guide the design of future catalysts. Moreover, methods to enhance the activity and selectivity are discussed to emphasize the unique advantage of electrocatalysis in overcoming the limitations of traditional thermal catalysis. Finally, immense opportunities and challenges for catalyst design are discussed by unifying thermal and electrochemical catalysis.

Selective Activation of Propane Using Intermediates Generated during Water Oxidation

“…Electrochemical methods provide promising avenues to circumvent this impediment because the external driving force (i.e., potential) can be controlled precisely. Moreover, as an anodic reaction, electrochemical oxidation of alkanes can be coupled with cathodic reactions, such as CO 2 or water reduction to produce hydrocarbons or hydrogen simultaneously. − Electrochemical devices also enable on-site transformation of alkanes where centralized steam reforming infrastructures are inaccessible . Previous research attempts include direct oxidation, oxidation using metal redox couples, − and oxidation using free radicals generated in a coupled oxygen reduction reaction (ORR) .…”

Molecular Dynamics and Machine Learning in Catalysts

“…Discovering the simple standard features that influence the properties in a small group of materials as descriptors is a valuable approach in properties prediction, such as catalytic activity and materials finding [141][142][143][144][145][146][147][148][149]. Several descriptors can be used, e.g., interatomic distance, nearest neighbor coordination number (CN), surface strain, the number of facets, and p-band center [150].…”

Splitting dioxygen over distant binuclear transition metal cationic sites in zeolites. Effect of the transition metal cation

“…Very recently, a breakthrough [12] in the activation of dioxygen [4] has been achieved. The distant binuclear cationic Fe(II) centers in Fe‐ferrierite are on the one hand close enough to cooperate in a four electron process of the activation of dioxygen but on the other hand far enough that a formation of an oxo‐bridge species known for metalloenzymes [4,5] is not possible and splitting dioxygen occurs even at room temperature [4].…”