Catalytic properties of Ga-substituted ZSM-5 zeolite in propane aromatization

A Ga-substituted ZSM-5 zeolite was successfully synthesized via a hydrothermal synthesis method, and its catalytic performance and physicochemical properties in propane aromatization were systematically investigated. Comprehensive characterizations including XRD, SEM, ICP-AES, IR, NH 3 -TPD, XPS, N 2 adsorption-desorption and TG analyses revealed that Ga species exhibited the lower tendency to incorporate into the ZSM-5 zeolite framework compared to Al species. The gallium-doped aluminosilicate (GaAlZ5), possessing the largest specific surface area and highest acid content, demonstrated a superior aromatic selectivity of 85.6% and propane conversion of 66.1%, which exceeded those of gallosilicate (GaSiZ5) by 22.5% and 5.6%, respectively. Moreover, the intergranular mesopores in GaAlZ5 enhanced the mass-transfer rate of aromatics, effectively suppressed the formation of coke precursors, and endowed the catalyst with excellent long-term stability as well as regeneration stability. This work provides a facile synthesis strategy and systematic theoretical support for the design of high-stability and high-selectivity Ga-based zeolite catalysts for propane aromatization. Graphical abstract This graphical abstract illustrates the bifunctional tandem pathway of propane aromatization, where propane is activated to propylene via dehydrogenation over Ga-based Lewis acid sites, followed by aromatization under the synergy of Brønsted and Lewis acid sites. This work reports a Ga-modified ZSM-5 zeolite (GaAlZ5) with optimized acid properties and pore structure, which delivers 66.1% propane conversion and 85.6% aromatics selectivity with excellent recyclability, providing a facile approach for light alkane valorization.