Enhancing the Reaction of CO2 and H2O Using Catalysts within a Nonthermal Plasma

The direct conversion of emitted and captured carbon dioxide into usable fuels remains a significant challenge and is a key element in the transition to net zero. Herein, we examine the reaction of CO2 and H2O over Ni- and Cu-based catalysts combined with nonthermal plasma (NTP) technology. The catalysis under NTP conditions enabled significantly higher CO2 conversion and product yield, which was almost six times higher than that of the plasma-only system. A maximum H2 concentration of ∼2500 ppm was achieved for the Cu/ZSM5 catalyst at 17% CO2 conversion. Comprehensive catalyst characterization together with the reaction performances reveals that Cu in a reduced state promotes both the CO2 and H2O conversion leading to H2 formation. In situ diffuse reflectance infrared spectroscopy (DRIFTS) coupled with mass spectrometry (MS) analysis of the gas phase products confirms that CO is the major active species to drive the water gas shift reaction to form H2 in addition to the direct CO2 and H2O interaction. It also explains how the different metal support interactions influence the CO adsorption and its interaction with water. Among the catalysts studied, ZSM5-supported Cu catalysts were found to be the most effective in facilitating the CO2 and H2O reaction to produce H2.