Laser Solid-Phase Synthesis of Robust Single-Atom Catalysts for CO2 Hydrogenation to Methanol

Abstract

The robustness of single-atom catalysts (SACs) is a critical concern for practical applications, especially for thermal catalysis at elevated temperatures under reductive conditions. In this study, a laser solid-phase synthesis technique is reported to fabricate atom-nanoisland-sea structured SACs for the first time. The resultant catalysts are constructed by Pt single atoms on In₂O₃ supported by Co₃O₄ nanoislands uniformly dispersed in the sea of reduced graphene oxide. The laser process, with a maximum temperature of 2349 K within ~100 μs, produced abundant oxygen vacancies (up to 70.8%) and strong interactions between the Pt single atoms and In₂O₃. The laser-synthesized catalysts exhibited a remarkable catalytic performance towards CO₂ hydrogenation to methanol at 300°C with a CO₂ conversion of 30.3%, methanol selectivity of 90.6% and exceptional stability over 48 h without any deactivation, outperforming most of the relevant catalysts reported in the literature. Characterization of the spent catalysts after testing for 48 h reveals that the Pt single atoms were retained and the oxygen vacancies remained almost unchanged. In situ diffuse reflectance infrared Fourier transform spectrum was conducted to establish the reaction mechanism supported by the density functional theory simulations. It is believed that this laser synthesis strategy opens a new avenue towards rapidly manufacturing highly active and robust thermal SACs.