Enhanced selective hydrodechlorination of 1,2-dichloroethane to ethylene on Pt–Ag/TiO2 catalysts prepared by sequential photodeposition

TiO2 supported Pt–Ag bimetallic catalysts were prepared using a sequential photodeposition method (denoted as pd-Pt–Ag/TiO2). For comparison, supported bimetallic catalysts were also prepared using the conventional impregnation method (denoted as im-Pt–Ag/TiO2). The catalysts were characterized by X-ray diffraction, transition electron microscopy, CO chemisorption, IR spectroscopy of CO adsorption, and X-ray photoelectron spectroscopy. Characterization results indicated that photodeposition led to site-specific deposition of metallic Ag domain on the surface of Pt particles and thus to the formation of core–shell (Pt@Ag) like bimetallic species, which effectively blocked the adjacent Pt sites. However, Pt–Ag ensemble was predominant in im-Pt–Ag/TiO2. Accordingly, hydrodechlorination of 1,2-dichloroethane exhibited substantially higher ethylene selectivity and catalytic stability on pd-Pt–Ag/TiO2 than on im-Pt–Ag/TiO2 at similar Ag loading levels. Findings from this study highlight the potential of using sequentially photodeposited core–shell like bimetallic catalysts to enhance the ethylene selectivity in hydrodechlorination of 1,2-dichloroethane.

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► TiO2 supported Pt–Ag bimetallic catalysts (pd-Pt–Ag/TiO2) were prepared by a sequential photodeposition method.
► Photodeposition of Ag on Pt/TiO2 led to preferential growth of Ag on Pt particle surface, which effectively blocked the adjacent Pt sites.
► Given similar Ag loading the pd-Pt–Ag/TiO2 catalyst displayed much higher catalytic stability and ethylene selectivity than the catalyst prepared by the impregnation method.