Bimetallic NiAg supported on aminopropyl-functionalized periodic mesoporous organosilica as a reusable catalyst for CO2 conversion to value-added chemicals

Abstract

Transforming CO₂ into more valuable chemicals has gained great interest due to greenhouse gas and climate change related issues. In this study, we performed CO₂ hydrogenation using a bimetallic nickel-silver catalyst supported on periodic mesoporous organosilica (NiAg/NH₂-pr-Ph-PMO). The NH₂pr-Ph-PMO was prepared via a co-condensation method, and NiAg was was incorporated using a simple wet impregnation process. Physicochemical properties of the catalyst were thoroughly characterized using FTIR, XRD, SEM-EDX, TEM, and BET-BJH. The synthesized NiAg/NH₂pr-Ph-PMO exhibited excellent properties, including a large surface area (793.5 m²/g) and uniform metal distribution. The optimal conditions for CO₂ hydrogenation found in this study were 225 °C, 2 bar, and a CO₂/H₂ ratio of 1:5. Under these conditions, conversion of CO₂ reached 38.34 % with 86.89 % selectivity towards formaldehyde production. Furthermore, NiAg/NH₂pr-Ph-PMO exhibits fine catalytic stability with the CO₂ conversion maintained above 35 % after 4 reaction cycles. FTIR analysis indicates no significant structural damage on the used catalyst, highlighting its robustness. This study showcases the excellent performance of the novel catalyst in converting CO₂ into more valuable chemicals.