Insights into CO ₂ Hydrogenation to DME: In Situ DRIFTS Study of Reaction over Cu/ZSM‐5 Catalyst

Abstract This study has employed in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) to generate mechanistic insights into CO 2 hydrogenation to dimethyl ether (DME) via methanol (MeOH) formation followed by dehydration. DRIFTS spectra were captured in situ using low loading Cu/ZSM‐5, at temperatures ranging from 100 to 300 °C and pressures of 1–25 bar. MeOH peaks were identified at 1005, 1031, and 1056 cm −1 , whereas DME peaks appeared at 1464, 1228, 1192, and 1120 cm −1 . Enhanced selectivity for DME was observed at 25 bar and 250 °C, favoring the formate pathway, with monodentate formate peaks at 1482 and 1350 cm −1 . DRIFTS data were collected for CO 2 flow only and a 20 % CO 2 /H 2 mixture (1:4) at 25 bar and 250 °C to study the reaction mechanism over time.