Thermal stable Pt clusters anchored by K/TiO2–Al2O3 for efficient cycloalkane dehydrogenation

Abstract

Catalytic dehydrogenation of cycloalkanes is considered a valuable endothermic process for alleviating the thermal barrier issue of hypersonic vehicles. However, conventional Pt-based catalysts often face the severe problem of metal sintering under high-temperature conditions. Herein, we develop an efficient K₂CO₃-modified Pt/TiO₂–Al₂O₃ (K–Pt/TA) for cycloalkane dehydrogenation. The optimized K–Pt/TA showed a high specific activity above 27.9 mol·mol⁻¹·s⁻¹(H₂/Pt), with toluene selectivity above 90.0% at 600 °C with a high weight hourly space velocity of 266.4 h⁻¹. The introduction of alkali metal ions could generate titanate layers after high-temperature hydrogen reduction treatment, which promotes the generation of oxygen vacancy defects to anchored Pt clusters. In addition, the titanate layers could weaken the surface acidity of catalysts and inhibit side reactions, including pyrolysis, polymerization, and isomerization reactions. Thus, this work provides a modification method to develop efficient and stable dehydrogenation catalysts under high-temperature conditions.