Ultralow-Content Pt-Catalysts with Enriched Oxygen Vacancies for Highly Efficient Hydrogenation of MEA-Captured-CO ₂ to Methanol

High Resolution Image Download MS PowerPoint Slide Direct hydrogenation of MEA-captured-CO 2 to methanol is likely to be an economically advantageous technology for mitigating CO 2 emissions and storing energy in a decentralized manner. However, the current catalysts have low activity and significant N -methylation selectivity when converting carbamate species to methanol via formamide intermediates. Building on our previous work, this manuscript presents the development of an ultralow-loading Pt-catalyst (0.0127 wt % Pt/C SAP -TiO 2 -CeO 2 ) with abundant oxygen vacancies. This novel catalyst demonstrates significantly improved efficiency in the direct hydrogenation of MEA-captured-CO 2 to methanol, achieving methanol turnover numbers (TONs) of up to 30252. The metal loadings, temperatures, CO 2 loadings, and catalyst recycling stability were thoroughly evaluated. Comprehensive structural and surface characterizations (XRD, SEM, ac-HAADF-STEM, BET, XPS, and CO 2 -TPD) reveal that the positively charged Pt is highly likely atomically dispersed and predominantly anchored on the superabsorbent polymer (SAP)-derived hierarchical porous carbon skeleton (C SAP ) in the well-defined carbon-metal-oxide-composite support with rich oxygen vacancies. We proposed a rational mechanism featuring oxygen vacancy-assisted supramolecular heterogeneous single-atom catalysis for carbamate adsorption, preorganization, activation, and conversion to methanol.