Direct Coupling of Methane and Carbon Dioxide on Tantalum Cluster Cations

Understanding molecular-scale reaction mechanisms is crucial for the design of modern catalysts with industrial prospect. Through joint experimental and computational studies, we investigate the direct coupling reaction of CH4 and CO2, two abundant greenhouse gases, mediated by Ta-1,4(+) ions to form larger oxygenated hydrocarbons. Coherent with proposed elementary steps, we expose products of CH4 dehydrogenation [Ta1,4CH2](+) to CO2 in a ring electrode ion trap. Product analysis and reaction kinetics indicate a predisposition of the tetramers for C-O coupling with a conversion to products of CH2O, whereas atomic cations enable C-C coupling yielding CH2CO. Selected experimental findings are supported by thermodynamic computations, connecting structure, electronic properties, and catalyst function. Moreover, the study of bare Ta-1,4(+) compounds indicates that methane dehydrogenation is a significant initial step in the direct coupling reaction, enabling new, yet unknown reaction pathways.

Automated summary

Understanding molecular-scale reaction mechanisms is critical for designing effective catalysts. This study investigates the direct coupling reaction of CH4 and CO2 mediated by Ta-1,4(+) ions. Experimental results show that methane dehydrogenation is a significant initial step in this reaction, and ion catalysts facilitate the formation of more complex products.