Catalytic propane dehydrogenation by anatase supported Ni single-atom catalysts

With the increasing production of propane from shale gas and the growing demand for propylene, propane dehydrogenation (PDH) has gained significant attention as a promising route for the on-purpose production of propylene. As a cheap yet efficient catalyst, Ni-based catalysts have attracted interest because of its ability to activate alkane. Single-atom catalysts (SACs) can maximize the metal atom utilization. Here, we demonstrate that anatase TiO 2 supported Ni SAC (Ni 1 /A-TiO 2 ) exhibits not only superior intrinsic activity and propylene selectivity but also much better stability than the corresponding Ni nanoparticle (NP) catalyst (Ni NP /A-TiO 2 ) in PDH reaction at 580 °C. The rate of propylene production on Ni 1 /A-TiO 2 is about 1.96 mol C3H6 g Ni −1 h −1 , about 65 times higher than that of Ni NP /A-TiO 2 sample (0.03 mol C3H6 g Ni −1 h −1 ). In combination of high-angle annular dark-field scanning transmission electron microscopy, in-situ diffuse reflectance infrared Fourier transform spectra, in-situ X-ray photoelectron spectroscopy and X-ray absorption spectroscopy characterizations, we confirm that the Ni SAC mainly contains individual Ni atom singly dispersed on the support in positive Ni (II) valence state. In addition, as a result of strong metal-support interaction (SMSI) between Ni NP and TiO 2 carrier under reduced conditions, the Ni NPs sites are encapsulated by TiO x overlayer (~2 nm thick) thus display poor reaction performance.