An operando XAS/d-PDF study on the structural evolution of Pd-Ga bimetallic catalyst for CO2 hydrogenation to methanol

Pd-Ga-based catalysts are promising for CO2 hydrogenation to methanol, exhibiting superior activity and stability compared to Cu-based catalysts. Although Pd performs poorly in this reaction, adding a second metal such as Ga leads to a drastic improvement in the catalytic activity and selectivity, possibly due to modification of the electronic and/or geometric local structure of Pd. However, there is still limited knowledge about the active sites in these bimetallic Pd systems. This proposal aims to gain insight into the structural dynamics of bimetallic Pd-GaOx/SiO2 catalysts for the catalytic CO2 hydrogenation to methanol under an H2 pre-treatment and under reaction conditions. We propose operando X-ray absorption spectroscopy (XAS), combined with differential pair distribution analysis (d-PDF) of X-ray total scattering data to shed light on the atomic-to-the-nanoscale structure of this complex system.