In-situ CO2 methanation diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) experiment was carried out using a Bruker INVENIO-S spectrometer. The catalyst was in-situ reduced in a Harrick Praying Mantis chamber at 200 C under H2 for 1 h and flushed under He for 30 min. A background spectrum was then taken in He atmosphere for each reaction temperature. For background subtraction, the spectra were scaled such that the  Si-O vibrational frequency at 1865 cm -1 was absent . During CO2 methanation DRIFTS experiment, a gas mixture comprising 8 mol% CO2, 32 mol% H2 and He balance was flowed into the chamber, which was set to the desired temperature from 50 °C to 300 °C. The spectra were collected after a steady state was attained at each temperature.