Synergistic High Entropy Effect and Coke Resistance Capability toward Stable Catalyst Design for CO2-assisted C3H8 Dehydrogenation

Propylene, a key building block in the chemical industry, can be selectively produced via CO2-assisted propane dehydrogenation (CO2-ODP), a promising alternative to traditional steam cracking with the potential for carbon mitigation. However, catalyst deactivation due to sintering and coking remains a major challenge. Herein, we develop a series of high-entropy intermetallic (HEI) catalysts of the form (Pt0.33CoxNi0.67-x)(Sn0.57In0.43)/CeO2, systematically tuning the Co content and configurational entropy to disentangle the roles of structure and composition in catalytic performance. The optimal composition with x = 0.40 demonstrates the longest lifetime (80 h), high propylene selectivity, and superior coke resistance. CO pulse chemisorption and temperature-programmed oxidation (TPO) reveal that high Co loading promotes CO2 activation and coke combustion, while increased configurational entropy significantly enhances nanoparticle dispersion retention. A strong positive correlation between entropy and dispersion retention is established and further validated using a series of compositions with increasing ΔSconf. Three-cycle regeneration experiments confirm that deactivation arises mainly from carbon accumulation rather than irreversible structural degradation. This work provides the first quantitative link between entropy, dispersion, and thermal stability in HEI catalysts, offering a rational design strategy for robust and regenerable CO2-ODP systems.