Soft template-induced deep pore structure of Cu/Al2O3 for promoting plasma-catalyzed CO2 hydrogenation to DME

Abstract

Plasma-activated heterogeneous catalysis is a promising strategy for catalytic CO₂ hydrogenation under mild conditions. In this study, pore structures with deep pore channels were constructed on Al₂O₃-x via a soft template method, and Cu/Al₂O₃-x was prepared by an impregnation method, with Al₂O₃-x serving as the support for plasma-catalyzed CO₂ hydrogenation to dimethyl ether (DME). Cu/Al₂O₃-0.75/HZSM-5 demonstrated a high performance and discharge efficiency for plasma-catalyzed CO₂ hydrogenation. The CO₂ conversion and DME yield for plasma-catalyzed CO₂ hydrogenation on Cu/Al₂O₃-0.75/HZSM-5 reached 21.98% and 9.83%, respectively, with selectivities for CO, CH₃OH, and DME on Cu/Al₂O₃-0.75/HZSM-5 of 25.39%, 29.89%, and 44.72%, respectively. The deep pore structures on Al₂O₃-x serve as Cu loading sites, and the confinement effect of the pores enhances the metal-support interaction and Cu metal dispersion. More abundant and stronger Brønsted basic and Lewis acidic sites facilitate the activation and hydrogenation of CO₂. Notably, the electric field formed by Cu sites anchored in the deep pore channel structures is conducive to guiding the activated plasma CO₂ intermediates into the difficult-to-access pores for hydrogenation. Hydrogenation of the plasma-activated CO₂ intermediates in the deep pore channels is crucial for improving plasma-catalyzed CO₂ hydrogenation to DME.