Photochemical route for synthesizing atomically dispersed palladium catalysts

Abstract

该工作由校内外多个课题组共同努力，历时三年多完成。我校郑南峰、傅钢等课题组紧密协作负责催化剂的合成、表征、催化测试及机理研究；中科院物理研究所谷林研究员主要负责催化剂的球差校正透射电子显微研究；加拿大达尔豪斯大学的张鹏课题组参与催化剂的同步辐射X-射线吸收谱研究。该研究工作的第一、二作者刘朋昕、赵云均为我校博士生。【Abstract】Atomically dispersed noble metal catalysts often exhibit high catalytic performances, but the metal loading density must be kept low (usually below 0.5%) to avoid the formation of metal nanoparticles through sintering. We report a photochemical strategy to fabricate a stable atomically dispersed palladium–titanium oxide catalyst (Pd 1 /TiO2 ) on ethylene glycolate (EG)–stabilized ultrathin TiO2 nanosheets containing Pd up to 1.5%.The Pd 1 /TiO2 catalyst exhibited high catalytic activity in hydrogenation of C=C bonds, exceeding that of surface Pd atoms on commercial Pd catalysts by a factor of 9.No decay in the activity was observed for 20 cycles. More important, the Pd 1 /TiO2 -EG system could activate H2 in a heterolytic pathway, leading to a catalytic enhancement in hydrogenation of aldehydes by a factor of more than 55.Supported by Ministry of Science and Technology of China grant 2015CB932303; National Natural Science Foundation of China grants 21420102001, 21131005, 21390390, 21133004, 21373167, 21573178, and 21333008; a NSERC CGS Alexander Graham Bell scholarship (D.M.C.); and a NSERC Discovery grant (P.Z.)