Fig. 2: Modulated excitation diffuse reflectance infrared Fourier transform spectroscopy (ME DRIFTS) during CO2 hydrogenation with the cobalt-based catalysts.
From: Uncovering the reaction mechanism behind CoO as active phase for CO2 hydrogenation
a Averaged time-resolved DRIFT spectra and b phase-resolved amplitude spectra of CoO (suffix: -ox) and metallic Co (suffix: -red) supported catalysts (T = 250 °C, P = 1 bar, H2/CO2 = 3). Adsorbed surface species with characteristic vibrational energies: c CO, d formyl, e formate, f carbonate, and g bicarbonate. h Simplified reaction pathways for cobalt-catalyzed CO2 hydrogenation to hydrocarbons. In the direct dissociation mechanism COads is an intermediate, which either desorbs or forms Cads. and then hydrocarbon products. The H-assisted mechanism involves surface carbonates, formates, and formyl as intermediates. The intermediates can either be fully hydrogenated to methane or converted into olefins or paraffins via C–C coupling (Fischer–Tropsch synthesis). Further details on experimental methodology and data analysis can be found in Supplementary Fig. 3.
