Tailoring Catalysts for CO₂ Hydrogenation: Synthesis and Characterization of NH₂-MIL-125 Frameworks

Copper nanoparticles have been integrated onto the framework of modified NH₂-MIL-125(Ti), a metal-organic framework (MOF), and evaluated as catalysts for converting CO₂ into valuable products. The modified MOF was achieved through a post-synthetic modification process involving the partial replacement of titanium with zirconium or cerium within the MOF's structure. The objective behind this alteration is to create a synergistic effect between the MOF, serving as a support matrix, and the embedded copper nanoparticles, thereby enhancing the performance of the catalyst. The obtained catalysts were characterized and evaluated in the hydrogenation of CO₂ to methanol under different experimental conditions, reaching CO₂ conversions of up to 5%, with a selectivity towards methanol that reached values of up to 60%. According to the obtained results, the catalyst composed of Ti, Zr and Cu stood out for having the highest CO₂ conversion and selectivity towards methanol, in addition to practically inhibiting the production of methane. These results demonstrate that the interaction of the framework with the Cu nanoparticles, and thus its catalytic properties, can be changed by modifying the properties of the MOF.