CO2 Hydrogenation to Methanol over Novel Melamine-Based Polyaminal Porous Polymer Coordinated to Cu-Based Catalyst

The catalytic conversion of carbon dioxide to methanol is significantly important both practically and scientifically for the reduction in CO2 emissions. Furthermore, it can partially address the issue of human reliance on non-renewable resources. The main motivation of this study is to use a melamine polymer network to support a copper-based catalyst for CO2 hydrogenation to methanol. Based on Schiff base chemistry, a facile catalyst-free process, a novel porous polyaminal polymer (MGPN) was prepared with nitrogen contents as high as 38%. MGPN was used as a support for Cu-based catalyst and applied in CO2 hydrogenation to CH3OH under mild conditions. A deep characterization of the MGPN@CuO/ZnO/Al2O3 catalyst was made through FTIR, N2 adsorption–desorption, SEM-EDS, TEM, TGA, XRD, CO2-TPD, and H2-TPR techniques. The CO2 hydrogenation study was performed in a fixed bed reactor with a residence time of 1.104 s on varying parameters such as the metal loading, catalyst amount, flow rate, pressure, calcination temperatures, reduction temperatures, and catalytic reaction temperature profile. The space-time yield (STY) of 145.43 mgmethanol·gcatalyst−1·h−1, a selectivity of 98.36%, and CO2 conversion of 11.76% were obtained under an economically and energetically sustainable low-pressure (1 MPa) and 260 °C hydrogenation process.