Enhancing C-H Bond Activation of Methane via Temperature-Controlled, Catalyst-Plasma Interactions

Recent shale gas discoveries and advances in plasma chemistry provide the basis to exploit metal surface-plasma interactions to precisely control C-H bond activation on catalytic surfaces, leading to improved reaction efficiencies. Although the exact determination of plasma-catalyst interactions remains a topic of continuing research, this Letter provides evidence that plasma catalyst interactions exist and can be used to significantly enhance the activation of C-H bonds at temperatures >630 K, probed by the catalytic dry reforming of methane with carbon dioxide using Ni/Al2O3. We systematically varied bulk temperature and plasma power to determine Ni plasma interactions. In contrast to reactions at low temperatures (<630 K), CH4 conversion, H-2 yield (selectivity), and forward CH4 consumption rate were significantly enhanced at higher temperatures with plasma (>8 fold increase). Other competing contributors, such as gas-phase plasma reactions, charge confinement, and plasma-driven enhanced bulk gas temperatures, played minor roles when operating at temperatures >630 K.