Stabilization of an Ethoxy-Mediated Pathway over Cs-Modified Pd/ZnO Unlocks Highly Selective Photocatalytic Oxidative Dehydrogenation of Ethane

Abstract

Photocatalytic oxidative dehydrogenation of ethane (ODHE) is a promising mild route to ethylene; however, the entanglement of reactive intermediates triggers uncontrollable competing pathways, limiting both yield and selectivity. Herein, we report an efficient and highly selective photocatalytic ODHE process proceeding via a stabilized ethoxy-mediated pathway over Cs-modified Pd/ZnO catalysts. The optimized Cs-modified Pd/ZnO catalyst delivers an ethylene production rate of 14.6 mmol g–1 h–1 with a selectivity of 95.2%, along with robust stability over 15 h of continuous operation, outperforming most photo- and thermocatalysts reported in the literature. In situ and time-resolved spectroscopic characterizations reveal that Cs promotion generates interfacial Pd–Ov dual active sites, which synergistically enhance ethylene formation by improving spatial charge separation, facilitating oxygen activation, and, critically, steering selective C–H activation via stabilized ethoxy intermediates. This work not only elucidates the fundamental mechanism of photocatalytic ODHE but also demonstrates that dopant-induced interfacial engineering spatially decouples active sites, effectively disentangling competing pathways in intricate photocatalytic reactions.