Remarkable Activity of 002 Facet of Ruthenium Nanoparticles Grown on Graphene Films on the Photocatalytic CO2 Methanation

In the context of diminishing atmospheric CO2 emissions, there is an urgent need to develop processes that can be carried out at a scale commensurate with appropriate CO2 volumes. One possible reaction is the transformation of CO2 to methane (Sabatier reaction). Due to its chemical stability, catalytic CO2 hydrogenation to methane is carried out at temperatures of 450 °C or higher and pressures above 5 bars, thus, requiring a significant energy input. One alternative possibility to conventional thermal catalysis is the use of solar light as the primary energy, performing the photocatalytic CO2 hydrogenation. In this broad context, the present study shows the photocatalytic activity of nanometric films of oriented Ru nanoparticles (NPs) strongly grafted on defective graphene. These graphene films (thinner than 20 nm) containing Ru NPs nanoplatelets (less than 2 nanomolRu/cm2) are among the most active photocatalysts ever prepared for CO2 hydrogenation and operate through photoinduced charge separation. Nanometer‐thick films of graphene obtained from biomass having minute amounts of facet‐oriented Ru nanoparticles (NP) are reported. Thorough characterization shows that the 002 crystallographic facet of the Ru NPs possesses a remarkable activity for CO2 hydrogenation at a low temperature (150 °C) and operates through photo‐induced charge separation placing the photocatalyst among the highest active materials ever reported.