(599e) Preparation of Pt/ZrO2 Catalyst with Different Morphologies for the Selective Hydrogenation of Vegetable Oil

In the field of food industry, a large amount of trans fatty acids are produced during the hydrogenation of vegetable oils. Scientific studies have shown that high intake of trans fatty acids can cause cardiovascular disease. As the requirement of trans fatty acids in food becomes more and more strict, it is imperative to reduce the content of trans fatty acids in hydrogenated vegetable oils. Therefore, reducing the formation of trans fatty acids during hydrogenation has important engineering practical implications. However, trans fatty acids are more easily generated during the reaction. In order to overcome this adverse effect, designing a catalyst that can accelerate the formation of cis fatty acids is an ideal method to improve the reaction selectivity. At present, monatomic catalysts are widely used in hydrogenation because of their better catalytic performance and higher atomic utilization. In this work, the single-atom Pt catalysts supported on ZrO₂ with different morphologies (monoclinic structure, tetragonal structure, cubic structure) were prepared as highly efficient and stable catalysts for selective hydrogenation of vegetable oil. The prepared single-atom Pt/ZrO₂ catalyst (tetragonal structure) had a high cis fatty acid yield (about 50%). According to the reaction results, the catalytic performances of Pt/ZrO₂ catalysts with different morphologies were different. XPS and O₂-TPD showed that there were abundant oxygen vacancies on the surface of ZrO₂, and the number of oxygen vacancies on the surface of ZrO₂ with different morphologies was different. Combined with the results of reaction and in-situ infrared analysis, these oxygen vacancies can regulate the electronic structure on the surface of the catalyst, enhance the electron enrichment, and promote the adsorption and activation of reactants. DFT calculation showed that oxygen vacancies on Pt/ZrO₂ catalyst (tetragonal structure) affected the adsorption form of the C=C bond, thus promoting the formation of cis fatty acids.