(258a) Insights into the Relationship between Structure and Reactivity Descriptors in Realistic Nanoparticle Models: A DFT Approach

Fischer–Tropsch (FT) synthesis is a promising road for the conversion of syngas into valuable hydrocarbons such as gasoline, diesel, chemicals and so forth. The chemical reactions are catalyzed more commonly by transition metals including Fe, Co and Ru. Albeit, only Fe and Co catalysts are commonly employed in industry. Due to the various steps involved during the conversion and the variety of products that can be generated, significant variation in catalyst composition and shape affects the nature and content of the products. That is, the catalytic activity of metal nanoparticles is greatly size-dependent and even just an additional atom can entirely change the reactivity and stability. Due to encouraging results with previous studies on 13-atom cluster models of Co, Fe, Ni, Pd, Pt, and Ru, we are now exploring 55-atom cluster models of the same metals using Density Functional Theory (DFT) calculations. These cluster models have shown to retain the accuracy of the periodic slab models at a lower computational cost. Since experimental information at the atomic level is difficult to obtain, we carried out systematic DFT calculations for evaluating reactivity descriptors of larger models. These cluster-based models offer a platform for the study of the adsorption and desorption of CO and H2 at the initial stages of the FT synthesis.