To reduce our reliance on petroleum for energy and chemicals, it is vital to engineer chemical reactions that sustainably produce fuels and platform molecules using renewable electricity. One such reaction is dry methane reforming (DMR) that converts methane (CH4) and carbon dioxide (CO2) into more valuable carbon monoxide (CO) and hydrogen (H2) but requires high temperatures to activate CH4 and regenerate catalysts deactivated by coking. Non-thermal plasma (NTP)-assisted catalysis is an emerging electrified approach that can activate CH4 and CO2 at near-ambient temperature and pressure; the catalyst can direct selectivity to desired products, while surface interactions can (beneficially) influence the NTP. A key challenge in effective catalyst design and NTP implementation is to fundamentally understand the complex plasma/catalyst interactions during reaction. In this work, we utilized a dielectric barrier discharge (DBD) plasma jet with operando diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) to probe relevant surface intermediates during plasma reaction on supported Pt catalysts, complemented with packed bed DBD reactor data. NTP-assisted CO oxidation was studied to probe plasma-induced changes to CO–Pt binding, which elucidated nanoparticle restructuring due to O2-derived species. NTP-assisted methanol decomposition was examined to interrogate stability and reactivity of DMR intermediates, which demonstrated that methoxy conversion to formates and carbonates depended on plasma identity (CO2, O2, CH4, Ar, etc.). Mechanistic insights gleaned from spectroscopic analyses contextualized packed bed DBD studies of NTP-assisted DMR. The delta between NTP-assisted DMR rates and thermal DMR rates normalized per mol surface Pt of supported Pt on alumina, silica, and zeolite 3A increased exponentially with temperature; the selectivities to CO, H2, ethane, and water varied among metal-free and supported metal catalysts, reflecting changes in relative rates of competing reaction pathways. These insights advance the mechanistic understanding of NTP-assisted DMR and are vital for developing plasma-assisted catalytic reactors for sustainable energy applications.
