Hydrogenation of CO2 to Propane and n -Butane by Engineering Metal Oxide Interfacial Structure and Manipulating Zeolite Pore Structure and Acidity

Abstract

Abstract Selective hydrogenation of CO2 to propane and n-butane is of great interest, as these two compounds are not only primary components of liquefied petroleum gas (LPG) but also crucial raw materials for preparing propene and a degradable plastic precursor of succinic acid. Although various composite catalysts combining metal oxides and zeolites have been explored, their catalytic performances remain insufficient. Here, we found that ZnZrOx decorated with ultrasmall FeOx clusters, forming an intimate FeOx–ZnZrOx interfacial structure, showed high catalytic activity for CO2 hydrogenation to methanol due to a strong CO2 adsorption capacity and H2 dissociation ability, and silicoaluminophosphate molecular sieve with RHO topological structure enhanced methanol conversion into propane and n-butane via hexamethylbenzenes as active hydrocarbon pool species owing to its unique supercage structure and double eight-membered ring pore opening. As a result, coupling of these two materials delivers a CO2 conversion of ∼66% and a (propane + n-butane) selectivity of 82% in hydrocarbons, which leads to a (propane + n-butane) yield of ∼42%. It is surprising that this composite preferentially produces n-butane rather than iso-butane, and the n-butane/iso-butane ratio is higher than 85.8. The high catalytic stability of this composite is demonstrated by maintaining CO2 conversion, (propane + n-butane) selectivity in hydrocarbons, and their yield of ∼ 61%, ∼ 77%, and ∼ 31%, respectively, after a reaction of 620 h. This work not only fabricates a high-performance catalyst for CO2 hydrogenation to propane and n-butane by engineering the metal oxide interfacial structure and manipulating the zeolite’s pore structure and acidity, but also makes it possible to develop an efficient way for preparing propene and succinic acid from CO2 hydrogenation.