Structure Robustness of Highly Dispersed Pt/Al₂O₃ Catalyst for Propane Dehydrogenation during Oxychlorination Regeneration Process

The structure and performance stability of a Pt-based catalyst for propane dehydrogenation during its reaction-regeneration cycles is one of the key factors for its commercial application. A 0.3% Pt/Al2O3 catalyst with a sub-nanometric particle size was prepared and two different types of regeneration processes, long-term dichloroethane oxychlorination and a reaction-oxidation-oxychlorination cycle, were investigated on this catalyst. The fresh, sintered and regenerated catalyst was characterized by HAADF-STEM, CO-DRIFTS, XPS, CO chemisorption and N-2 physisorption, and its catalytic performance for propane dehydrogenation was also tested. The results show that the catalysts tend to have a similar particle size, coordination environment and catalytic performance with the extension of the regeneration time or an increase in the number of cycles in the two regeneration processes, and a common steady state could be achieved on the catalysts. This indicates that structure of the catalyst tends to approach its equilibrium state in the regeneration process, during which the utilization efficiency of Pt is maximized by increasing the dispersion of Pt and its intrinsic activity, and the structural robustness is secured. The performance of the catalyst is comparable to that of a single-atom Pt/Al2O3 catalyst.