Defective TiO <i> <sub>x</sub> </i> overlayers catalyze propane dehydrogenation promoted by base metals
Sai Chen, Yiyi Xu, Xin Chang, Yue Pan, Guodong Sun, Xianhui Wang, Donglong Fu, Chunlei Pei, Zhi‐Jian Zhao, Dong Su, Jinlong Gong
Abstract
The industrial catalysts utilized for propane dehydrogenation (PDH) to propylene, an important alternative to petroleum-based cracking processes, either use expensive metals or metal oxides that are environmentally unbenign. We report that a typically less-active oxide, titanium oxide (TiO 2 ), can be combined with earth-abundant metallic nickel (Ni) to form an unconventional Ni@TiO x catalyst for efficient PDH. The catalyst demonstrates a 94% propylene selectivity at 40% propane conversion and superior stability under industrially relevant conditions. Complete encapsulation of Ni nanoparticles was allowed at elevated temperatures (>550°C). A mechanistic study suggested that the defective TiO x overlayer consisting of tetracoordinated Ti sites with oxygen vacancies is catalytically active. Subsurface metallic Ni acts as an electronic promoter to accelerate carbon-hydrogen bond activation and hydrogen (H 2 ) desorption on the TiO x overlayer.