Particle size effect in cobalt-based CO2 hydrogenation - tailoring selectivity to methanation or rWGS activity

Cobalt-based COx hydrogenation catalysts have become increasingly interesting to the scientific community as reports throughout the last decade have shown it acts as a versatile catalyst for the synthesis of a multitude of chemicals, ranging from hydrocarbons and olefins in Fischer-Tropsch, to aromatics and oxygenates. Via surface organometallic chemistry, an approach effective for the synthesis of model catalysts, we synthesized Cobalt nanoparticles on SiO2 with tailored surfaces and interfaces to be used as a platform to study distinct catalyst features and their catalytic consequences in COx hydrogenation. We observed activity in CO2 hydrogenation with selectivity being highly dependent on particle size. This implies a pronounced particle size effect (PSE), leading to either a potent rWGS or methanation catalyst. By operando x-ray absorption spectroscopy, we hope to elucidate the origin of this PSE, to link our data to the differences particle size is methodologically tailored.