Microwave Synthesis of Metallic Nanoparticles Supported on Porous Coordination Polymers: A Bi-functional Catalyst Design for CO₂ Activation and Conversion

Abstract

The efficient separation and conversion of CO₂ from power plant flue gases remains a significant and far reaching global goal. Partially, because of the high energy cost associated with CO₂ separation which makes technologies, such as amine scrubbing and conventional sorbent materials, less attractive. In this work we have used a microwave-assisted method to prepare Mg-based porous coordination polymers (MOF-74) with open metal sites. The material shows a high CO₂ uptake at room temperature mainly due to the high binding energy between the open Mg site (in the coordination polymer) and the oxygen atom of the adsorbed CO₂ molecule. Our results show that the microwave-based Mg-MOF-74 shows superior properties compared to thermally prepared samples such as higher surface area, crystallinity and CO₂ uptake. Pt nanoparticles (<5-10 nm) were deposited on the Mg-MOF-74 as manifested from the TEM results. The Pt nanoparticles were uniformly dispersed across the sample with more aggregations at higher Pt loadings. Different techniques were used to characterize the materials such as (BET surface area, XRD, SEM, EDS, TEM and TGA). These materials function as a bi-functional catalyst and sorbent material with the Mg-MOF-74 material responsible for CO₂ capture and supported Pt nanoparticles responsible for its catalytic activity.