Photoassisted amplification of chain-growth in CO2 hydrogenation: Switching selectivities of heterogeneously catalyzed reactions with light

Selective carbon-carbon bond formation is a major challenge for chemical transformations to meet the global sustainability targets, which requires game-changing concepts instead of further improvement of conventional catalyst materials. In this work, a new paradigm to tune the selectivity of thermal catalytic systems is presented by using light as an external trigger to switch the selectivity from pure reduction to carbon-carbon bond formation. In a ruthenium-catalyzed CO2 hydrogenation reaction, chain-growth is initiated through irradiation with light, eventually leading to the formation of higher hydrocarbons instead of solely methane. Photoassisted reaction control was differentiated from photokinetic and photothermal effects by sophisticated thermal imaging and kinetic modelling. A light-induced change of the sorption properties of the solid catalyst surface was identified as reason for the changes in selectivity. The results render the exploitation of photoassisted effects as highly potent general strategy for comprehensive reaction control of reactions catalyzed by solids.