Catalytic Descriptor Exploration for Ru-Based Fischer-Tropsch Catalysts: Effect of Chlorine and Sulfur Addition

As an important factor in the design of catalysts, catalytic descriptor exploration has emerged as a novel frontier in heterogeneous catalysis. Here, the underlying structure-activity relationships of Ru-based catalysts are theoretically studied to shed light on this area. Calculations of different competing reaction paths suggest that the HCO*-mediated path─because of two synergistic active sites─is more favorable than others. In addition, compared to unadulterated Ru catalysts, the presence of Cl enhances the hydrocarbon production, whereas the presence of S decreases it. After a systematic examination of a series of structure-activity relationships (42 in total), we found that both charge transfer and average charge difference of active Ru atoms are good descriptors for the binding stability of reactants. However, for reactivity the Gibbs free energy of the reactants performs better. More interestingly, due to the quite different catalytic processes of the dissociation and hydrogenation steps, their correlations have opposite slopes.