Solving the Conundrum of the Influence of Irradiation Power on Photothermal CO₂ Hydrogenation

Solar photocatalysis appears as a viable approach for the production of value-added chemicals from CO₂. However, up to now, there is no information on the influence of the light intensity on the product distribution of CO₂ hydrogenation and the modeling of the actual local temperature at the catalytic sites for typical nanoparticulate photocatalysts. Herein, it is shown that for a photothermal catalyst containing a high density of homogeneously distributed Ru nanoparticles, the collective heating prevails, resulting in a homogeneous temperature distribution in the material that should be relatively close to that of the support and that can be measured macroscopically. Moreover, light intensity has a clear influence on product distribution due to the differences in the local temperature, and therefore, attention should be paid to stable operating conditions, temperature, and CO₂ conversion that can result in remarkable differences in product selectivity for the same catalyst as a function of light intensity.