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

摘要

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, 1R 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.