Despite the considerable progress in carbon dioxide hydrogenation to various C1 chemicals, it is still a great challenge to synthesize value-added chemicals or fuels with two or more carbons, such as gasoline and olefins, directly from carbon dioxide, mainly due to its inertness and the difficulty in controlling the C–C bond formation. In collaboration with our experimental team, we developed a series of multifunctional catalysts by combining an indium oxide-based component for carbon dioxide hydrogenation to methanol and a zeolite-based component for methanol-to-hydrocarbons. By combining pure indium oxide and acidic HZSM5, we were able to directly transform carbon dioxide into gasoline-range hydrocarbons (C5-C11) with high selectivity via hydrogenation. Our experimental and computational studies suggested methanol as the key intermediate in this reaction. With a multifunctional catalyst consisting of zirconium-doped indium oxide and SAPO34, we were able to selectively convert carbon dioxide into lower olefins (ethylene, propylene, and butylene) by direct hydrogenation. Our computational study shows that the presence of the zirconium dopant on the indium oxide surface leads to higher oxygen vacancy formation energy, which in turn stabilizes the various adsorbates involved in carbon dioxide hydrogenation to methanol. One of the remaining challenges is the further suppression of carbon monoxide formation in this reaction, and we thus carried out systematic computational studies to investigate the elementary steps around carbon monoxide formation and hydrogenation, with the aim of designing oxide-based catalysts with improved catalytic performance for carbon dioxide hydrogenation to methanol, which can then be combined with a zeolite component for carbon dioxide conversion to hydrocarbons.

Mechanistic insights into dopant-enhanced carbon dioxide hydrogenation into hydrocarbons over indium oxide/zeolite multifunctional catalysts

256th National Meeting (2018)

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