Current Progress on Methods and Technologies for Catalytic Methane Activation at Low Temperatures

Abstract

Methane (CH 4 ) is an attractive energy source and important greenhouse gas. Therefore, from the economic and environmental point of view, scientists are working hard to activate and convert CH 4 into various products or less harmful gas at low-temperature. Although the inert nature of C-H bonds requires high dissociation energy at high temperatures, the efforts of researchers have demonstrated the feasibility of catalysts to activate CH 4 at low temperatures. In this review, the efficient catalysts designed to reduce the CH 4 oxidation temperature and improve conversion efficiencies are described. First, noble metals and transition metal-based catalysts are summarized for activating CH 4 in temperatures ranging from 50 to 500 °C. After that, the partial oxidation of CH 4 at relatively low temperatures, including thermocatalysis in the liquid phase, photocatalysis, electrocatalysis, and nonthermal plasma technologies, is briefly discussed. Finally, the challenges and perspectives are presented to provide a systematic guideline for designing and synthesizing the highly efficient catalysts in the complete/partial oxidation of CH 4 at low temperatures.

On the performance of the M–C (M = Fe, Ru, Os) unit toward methane activation

“…As shown in Table 2, in line with the [MC] + /CH 4 systems, the E g for [MCH] + and [MCH 2 ] + is correlated with the associated E TS . A few species, such as 1&3 OsCH + (singlet and triplet states), 1&3 RuCH + (singlet and triplet states), 3 though with a relatively low E g . Notably, the rather low E g for 1 OsCH + induces a barrierless methane activation without a transition state (see Fig.…”

“…1,2 Quite a lot of efforts have been made on the development of catalysts to activate methane at low temperatures. 3,4 For the rational design of high-performance catalysts, it is important to reveal the mechanistic aspects of H 3 C-H bond breaking processes at strictly a molecular level, through which a few influential factors may be addressed. To this end, gas-phase reactions are employed in order to avoid the obstacles induced by the heterogeneity of the active center morphology and the complexity of the chemical environment in condensed-phase transformations; 5,6 a series of structure-performance relationships have thus been concluded.…”

Stabilizing Pd–cerium oxide–aluminum oxide catalysts for methane oxidation by reduction pretreatments

“…The exhaust from these facilities and diesel engines gives out unburned methane and carbon dioxide and contributes to air pollution. Reviews [1][2][3][4][5][6] on catalytic oxidation of methane have highlighted the progress and challenges on the development of catalysts during the last forty years. Farrauto 7 highlighted the challenges of finding the most suitable catalyst material for the oxidation of methane that works at low temperatures and helps to address methane emissions in automobile exhaust gas abatement systems, namely high-temperature stability against sintering and resistance to poisons, such as S-containing molecules.…”