Exploring the Properties of Silica Nanomaterials on Supporting Bimetallic PtZn Sites for Direct Propane Dehydrogenation

The performance of metal sites in terms of their formation, evolution, and deactivation is strongly influenced by the properties of the supports during catalysis. Nanomaterials offer a tailorable size, shape, and composition, along with a large surface area, a high fraction of surface atoms, and unique electronic properties, thereby significantly improving the efficiency, selectivity, stability, and versatility of catalytic processes. In the direct dehydrogenation of propane (PDH) reactions, the activity, selectivity, and durability of catalysts face challenges due to the high reaction temperature and harsh atmosphere that accompanies the presence of reducible reactants. Herein, bimetallic platinum-zinc (PtZn) sites were synthesized on various silica nanomaterials to investigate the correlation between the nanoscale properties of silica and PDH performance. Among the supports being explored, including amorphous SiO₂ particles, mesoporous SBA-15, microporous silicate-1, and mesoporous MCM-41, MCM-41 stood out due to its distinctive advantages, including a large specific surface area, well-portioned pore size and distribution, and an appropriate amount and strength of acidic sites. Operating at a temperature of 600 °C, the catalyst exhibited a notable propene production rate of approximately 37.3 mmol·g_cat^-1·h^-1. This performance was coupled with an outstanding initial conversion (39.2%) and selectivity (97.7%) during the PDH reaction. The characterization results highlighted the exceptional dispersion of the PtZn sites on the MCM-41 support, showing remarkable resistance to coking and sintering throughout the reaction. These attributes exceeded those observed in other silica supports.