(569cl) Bifuntional Tandem Catalyst for Thermocatalytic CO2 Hydrogenation to Light Olefins

The quest for sustainable energy sources has led to intensified research in the field of direct CO₂ hydrogenation, provides a promising strategy to mitigate greenhouse gas emissions while producing valuable chemicals. Thermocatalytic CO₂ reduction to light olefins has gained much attention due to their high demand in plastics and textile industries. In this intended research, diverse approaches involving structural, promotional, and surface modification techniques were employed to enhance the efficacy of a bifunctional metal oxide zeolite-based tandem catalyst. In the zeo-type catalyst, SAPO-34 is subjected to alterations through metal cation cavity modifications via ion exchange, as well as surface modifications utilizing a core-shell structure strategy. Pristine SAPO-34 and ion-exchanged ZnSAPO-34 are combined physically with GaZrO mixed metal oxides, followed by comprehensive characterization using XRD, FTIR, SEM, TEM, N₂ physisorption, H₂-TPR, and CO₂-TPD techniques to assess the morphological, structural, and physiochemical properties of the synthesized bifunctional catalysts. The results showed that the zinc ion modification have substantially improved the surface acidity of SAPO-34 structure, enhancing the olefins selectivity. For surface modification, a novel fibrous SAPO-34 core-shell structure (SAPO-34@KCC-1) is prepared through a zeolite seed-assisted crystallization coupled with micro-emulsion method, employing varying weight ratios of SAPO-34 to TEOS. GaZrO metal oxide was dispersed over the fibrous SAPO-34 structure by sonochemical method. Different characterization analysis is subsequently conducted to comprehensively evaluate the structural, morphological, physical, and chemical properties of the resulting materials. SEM and TEM results revealed the successful synthesis of fibrous SAPO-34 structure along with bimetallic GaZrO phyllosilicates formation over fibrous core, leads to the high dispersion and strong interaction of metal oxides with the SAPO-34@KCC-1 support.