Direct conversion of carbon dioxide into liquefied petroleum gas over zeolite capsule catalyst

Abstract

The use of bifunctional catalysts, combining methanol synthesis and zeolite components, has been cleverly expanding to the hydrogenation of CO₂ into liquefied petroleum gas (LPG). However, such catalysts in this reaction displayed low catalytic efficiency due to the mismatch of the two components. In this study, an efficient strategy was realized via physically coating β zeolite onto the CuZnAl methanol catalyst, resulting in a shell thickness controllable core–shell encapsulated catalyst, denoted as CuZnAl@β. Sufficient characterization proves that the micro-coupling structure between methanol active sites and zeolite acid sites is designed reasonably and successfully, as consequently, the zeolite capsule catalysts embody a significant improvement toward LPG selectivity. Hence, the CuZnAl@β catalyst reached a high selectivity to LPG at 77.9% with 21.3% CO₂ conversion, under a reaction pressure of 2.0 MPa and a temperature of 320 °C. The strategy employed in this study could offer valuable insights into guiding catalyst design.