In situ infrared absorption probing of plasma catalysis: vibrationally-excited species induced Mars–van Krevelen type mechanism

Nonthermal plasma (NTP) assisted catalysis has recently received attention as an attractive technology that can overcome the energy barriers involved in conventional thermal catalysis. It is important to obtain fundamental insight into the synergistic effects arising from interactions between NTP-activated species and catalysis. However, it remains a challenge due to difficulties associated with the in situ characterization of NTP-activated species. In this study, CO was explored in dielectric barrier discharge by applying in situ transmission infrared (TIR) absorption spectroscopy; TIR enables the measurement of the vibrational temperature of CO while observing the surface reaction of excited CO to form intermediates species over wurtzite ZnO. The reaction behavior of activated CO correlates with the vibrational temperature of CO, showing vibrationally-excited CO reacts with lattice oxygen via the Mars–van Krevelen type mechanism; thus leading to higher activity compared with conventional thermal catalysis. This work helps to understand the fundamental chemistry and provides new insight into NTP-activated CO and its catalysis.