Pt<sub>3</sub>Ti Intermetallic Alloy Formed by Strong Metal–Support Interaction over Pt/TiO<sub>2</sub>for the Selective Hydrogenation of Acetophenone
Xixiong Zhang, Wen Shi, Yong Li, Wenning Zhao, Shaobo Han, Wenjie Shen
Abstract
The strong metal–support interaction over Pt/TiO 2 catalysts, which were prepared by depositing size-specified Pt colloids (2–6 nm) onto anatase TiO 2 nanosheets dominated by the reactive {001} facets, was featured by the formation of Pt 3 Ti intermetallic alloy and showed a size-dependent effect. After H 2 reduction at 773 K, bulk Pt–Ti alloys in a mixture of disordered and ordered phases were readily formed over 2 nm Pt particle, while Pt 3 Ti intermetallic alloys, with a thickness of up to 6 atomic layers, were observed on 4–6 nm Pt particles, showing as a Pt 3 Ti@Pt core–shell architecture where the Ti atom substituted the Pt atom periodically and interacted with the Pt atom electronically. By further raising the temperature for H 2 reduction to 873 K, the 2–6 nm Pt particles turned into well-crystallized Pt 3 Ti intermetallic alloys. Both bulk Pt–Ti and Pt 3 Ti intermetallic alloys suppressed considerably the chemisorption of H 2 and CO but dramatically promoted the selectivity for hydrogenating the C═O bond in acetophenone.