High CO₂ conversion via plasma assisted reverse water-gas shift reaction over Ag/ZnO catalyst

Abstract

Reverse water-gas shift reaction represents a strategic pathway for CO₂ utilization. Despite its potential, reverse water-gas shift reaction via conventional thermal-catalysis faces several challenges, including low equilibrium conversion rates due to thermodynamic constraints, high energy consumption, and insufficient product selectivity. Here, this study demonstrates an evident synergetic effect between plasma and Ag/ZnO, on enhancing reverse water-gas shift reaction. The plasma catalytic system achieved significantly improved performance with a remarkable CO₂ conversion rate of 76.5%, a high CO selectivity of 96.8%, and a CO yield of 74.1%, along with an energy efficiency as high as 0.19 mmol·kJ^–1, surpassing the plasma alone system and ZnO catalytic systems. Results from X-ray photoelectron spectroscopy and Auger electron spectroscopy confirm the presence of electronic metal-support interactions between Ag and ZnO, which facilitates the formation of electron-deficient Ag sites and partially reduced ZnO_x species. These reactive sites, along with oxygen vacancies created during reduction treatment, enhance the adsorption and activation of H₂ and CO₂, offering a dominant plasma-assisted surface reaction pathway for the improved reverse water-gas shift reaction. These findings underscore the crucial role of electronic metal-support interactions in manipulating surface environments to facilitate efficient plasma-assisted catalytic reactions, with significant implications for the rational design of catalysts capable of converting CO₂ efficiently under mild conditions.

Graphical abstract

Keywords

non-thermal plasma catalysis / CO₂ conversion / reverse water-gas shift reaction / Ag/ZnO / electronic metal-support interactions

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The Author(s) 2025