Defective TiO<i><sub>x</sub></i> overlayers catalyze propane dehydrogenation promoted by base metals.

Chen, Sai; Xu, Yiyi; Chang, Xin; Pan, Yue; Sun, Guodong; Wang, Xianhui; Fu, Donglong; Pei, Chunlei et al. · Science · 2024

basic_science · Level V

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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<sub>2</sub>), can be combined with earth-abundant metallic nickel (Ni) to form an unconventional Ni@TiO<i><sub>x</sub></i> 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<i><sub>x</sub></i> 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<sub>2</sub>) desorption on the TiO<i><sub>x</sub></i> overlayer.