New catalyst enables direct conversion of methane to high-value chemicals at room temperature

Efficiently converting methane (CH4) into valuable chemicals at room temperature using readily available molecular oxygen (O2) as an oxidizing agent is a sought-after method for methane utilization. However, this endeavor poses challenges due to methane’s chemical inertness and the relatively low reactivity of O2.

A recent breakthrough led by Prof. Deng Dehui and Assoc. Prof. Yu Liang from the Dalian Institute of Chemical Physics (DICP) at the Chinese Academy of Sciences (CAS) has achieved direct conversion of CH4 into C1 oxygenates (such as CH3OH, HOCH2OH, and HCOOH) at a mild room temperature of 25℃, thanks to an edge-rich MoS2 catalyst. This groundbreaking research was published in Nature Catalysis on September 21.

The conversion of methane into high-value chemicals has long been a formidable challenge due to methane’s low polarization rate and its high C-H bond energy (439 kJ mol-1).

Traditional catalytic approaches for CH4 conversion often require high temperatures (typically over 600℃), strong oxidants (like fuming sulfuric acid), or external influences (such as plasma). Unfortunately, such harsh conditions can lead to unwanted overoxidation, resulting in the formation of CO2.

The direct conversion of CH4 and O2 at lower temperatures, even at room temperature, is an enticing prospect for methane conversion. Yet, achieving this under mild conditions for C-H bond activation has proven difficult.

Through in-situ characterizations and theoretical calculations, the researchers demonstrated that the distinctive binuclear molybdenum (bi-Mo) sites within sulfur vacancies at the edges of MoS2 could effectively dissociate O2 to form active O=Mo=O* species at 25℃. These active species, in turn, activated the C-H bonds of CH4, driving the catalytic conversion of CH4 into C1 oxygenates via CH3O* intermediates at room temperature.

In their study, the researchers achieved an impressive CH4 conversion rate of up to 4.2% while maintaining a remarkable selectivity of over 99% for the desired C1 oxygenates during CH4 conversion with O2 at room temperature.

Source: Chinese Academy of Sciences

Leave a Comment