Atomically dispersed pd supported on zinc oxide for selective nonoxidative ethanol dehydrogenation

Abstract

Atomically dispersed Pd/ZnO was synthesized using a facile method. We found that 0.07 wta% Pd was isolated and positively charged on ZnO synthesized using a solvothermal method. By contrast, Pd clusters were formed on commercial ZnO, with the difference between the two supports residing in their different number of defects and surface area. Pd atoms are selective in the ethanol dehydrogenation reaction to form acetaldehyde and H2 exclusively, while Pd clusters decompose ethanol to form CO and CH4 as byproducts. Our work proves that the structure of Pd affects the selectivity of the reaction, and isolated Pd sites, unlike the contiguous Pd metal sites, catalyze the selective C-H bond scission while keeping the C-C bond intact. Pd atoms also showed higher stability in the reaction, since they did not suffer from coke formation. This work provides new insights to enable the design of selective and stable Pd-based catalysts for alcohol conversion reactions.