Highly efficient production of light olefins and para-xylene from n-pentane with a SiO2-coated Ga/ZSM-5 catalyst

The catalytic conversion of light paraffins into ethylene and propylene represents a highly efficient process, primarily due to their abundant availability and low cost. These factors confer a significant economic advantage, making this approach an attractive option for large-scale industrial applications. In this work, we designed a novel core-shell structured bifunctional catalyst of GaZ5-20Si, which combined reaction pathway modulation and shape-selective catalysis to simultaneously convert n-pentane into light olefins (ethylene, propylene, and butylene) and para-xylene as dominant products. By coating an external SiO2 layer, the external surface acid sites of the zeolite are successfully passivated, thereby suppressing the aromatic cycle and side reactions such as alkylation, which reduces catalyst coke formation and extends catalyst life. The total selectivity for light olefins and para-xylene reaches up to 63%, with para-xylene selectivity in the xylene fraction reaching as high as 93%. Moreover, no significant decline in catalytic performance was observed in an 80-hour reaction-regeneration cycle test. This work introduces an effective "SiO2 coating" strategy, enriching the pathways on the valueadded utilization of n-pentane.