Abstract
This study explores the methanol-to-olefins (MTO) performance of three SAPO-34 catalysts: SP (conventional), SPG1 (green, synthesized with okra mucilage as a hard template), and SPG (green, synthesized using a dual-template method with brewed coffee and okra mucilage). The dual-template strategy in SPG promotes the formation of a hierarchical micro-mesoporous structure, resulting in enhanced catalytic behavior. Structural and physicochemical characterizations (XRD, FT-IR, FESEM, EDS, N(2) adsorption-desorption, and NH(3)-TPD) confirm that SPG possesses smaller crystallites, higher mesoporosity, and moderated acidity compared to SP and SPG1. These features contribute to superior total olefin selectivity (89.8% at 240 min), higher ethylene selectivity (53.8%), lower propylene-to-ethylene (P/E) ratio, and improved catalyst stability. Furthermore, SPG exhibits reduced coke formation and better mass transport properties due to its tailored porosity. The utilization of renewable bio-templates not only enhances performance but also aligns with sustainable catalyst design. Overall, the SPG catalyst demonstrates significant potential for efficient and eco-friendly MTO processes.