POMASAC focused on the design, synthesis, and mechanistic understanding of advanced catalyst materials for light-assisted alkane activation and CO2-related transformations. A central activity was the development of metal-oxide-based and carbon-based catalyst platforms in which metals are stabilized as isolated atoms, small clusters, or highly dispersed sites. These materials were prepared using flexible and reproducible synthesis strategies, especially with combustion-based (or flash-conversion) approaches, which enable controlled tuning of catalyst composition, oxidation state, and defect structure.
In parallel with alkane activation studies, the project addressed electrochemical CO2 reduction pathways enabled by flash-converted metal-oxide catalysts. These systems were shown to promote selective CO2 reduction to formate under mild electrochemical conditions. Importantly, the generated formate was identified as a reactive intermediate capable of undergoing hydrogen-atom transfer (HAT), leading to the formation of the CO2 anion radical (CO2•–) species. This reactivity opens mechanistic routes by which CO2-derived intermediates can participate in subsequent bond-forming or bond-cleavage steps, linking CO2 conversion chemistry with alkane, or alkene, or even alkyne functionalization. The use of combustion-derived metal oxides was critical in stabilizing the active redox states and defect environments required for these coupled electron-proton transfer processes.
To support methane-relevant studies and ensure realistic reaction conditions, a dedicated methane gas handling and reaction setup was designed and installed. This included the integration of methane gas cylinders, mass-flow controllers, a potentiostat, and a custom photoelectrochemical glass reactor, allowing precise control of gas composition, flow rates, and irradiation conditions. The reactor system was coupled to a micro gas chromatograph (micro-GC) for reliable, time-resolved analysis of gaseous reaction products. This infrastructure enabled safe operation, reproducible testing, and quantitative evaluation of catalytic performance under controlled gas-phase conditions.
A stepwise experimental strategy was employed to facilitate robust mechanistic insights. Liquid model alkanes were first used to investigate sp3 C–H activation pathways under light-assisted conditions, allowing detailed analysis of reaction behaviour before extending insights toward methane chemistry using the dedicated gas-phase setup. In parallel, the same catalyst-design principles were applied to CO2-related reactions, demonstrating how metal dispersion, oxide defect chemistry, and support properties influence activity and selectivity across reduction and coupled transformation pathways. Extensive physicochemical and electrochemical characterization was conducted to correlate catalyst structure with performance. Advanced spectroscopic, microscopic, and electrochemical techniques were employed to track catalyst evolution under operating conditions and to establish structure-reactivity relationships across different catalyst families, including metal-oxide-embedded systems and carbon nitride single-atom catalysts.
The main achievements of the project include the establishment of transferable design principles for single-site/atom and oxide-embedded catalysts, the development of dedicated experimental infrastructure for methane (and alkane) and CO2 studies, the generation of original catalytic and mechanistic datasets, and the construction of a coherent framework linking atomic-scale structure to redox-driven chemical behaviour. Together, these outcomes provide a strong scientific foundation for future development of scalable and industrially relevant catalytic systems that integrate CO2 utilization with hydrocarbon activation.
