Abstract
Gas sources rich in CO(2) derived from biomass/waste gasification, anaerobic digestion, or industrial carbon capture often contain impurities such as H(2)S, H(2)O, and NH(3), which can significantly hinder catalyst performance. Here, we show the role of NH(3) on the reverse water-gas shift (RWGS) reaction over a commercial Cu/ZnO/Al(2)O(3) catalyst, examining its effects on both the catalytic activity and the catalyst structure. We found that NH(3) reversibly decreases CO(2) conversion immediately by suppressing carbonate hydrogenation and CO desorption. This effect intensifies with an increase in NH(3) concentration but decreases at higher temperatures. However, prolonged exposure (over 100 h) to RWGS conditions in the presence of 1.4% NH(3) leads to near-total and irreversible deactivation of the Cu/ZnO/Al(2)O(3) catalyst. Under NH(3) exposure, the catalyst loses Cu(+) sites on the surface, causing a spatial separation of Cu and ZnO. Finally, to address this challenge, we propose a novel strategy to mitigate NH(3) inhibition by decomposing NH(3) into N(2) and H(2).