Effect of plasma on catalytic conversion of CO2 with hydrogen over Pd/ZnO in a dielectric barrier discharge reactor

Abstract

In present work, the effect of dielectric barrier discharge (DBD) plasma on Pd/ZnO catalytic CO2 conversion under various discharge powers is investigated. An obviously enhanced CO2 conversion from 17.1% to 32.5% with the increasing of Pd content at 30 W can be observed. Catalyst microstructures with the presence of ZnO reduction were characterized by x-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), x-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (H2-TPR) and CO chemisorption. Moreover, plasma-excited CO2 temperature-programmed desorption (P-CO2-TPD) was carried out to reveal the changing of plasma excited CO2 activation on Pd/ZnO. Accordingly, Pd promoted ZnO reduction was found to influence both the amount and strength of CO2 activation with the presence of plasma, which therefore leads to a higher plasma-catalytic performance for CO2 conversion.Highlights•In DBD reactors, plasma excited CO2 activation plays a vital role for CO2 conversion.•Pd promoted ZnO reduction can influence both the amount and strength of CO2 activation under plasma.•Plasma-excited CO2 temperature-programmed desorption is used to reveal the changing of CO2 activation on Pd/ZnO.