Regulating surface hydroxyl coverage on PdAg alloys for selective electrocatalytic propylene oxidation to propylene glycol

The efficient and highly selective electrocatalytic oxidation of propylene to propylene glycol (PG) is a key challenge in green chemistry. Here, we synthesized uniform palladium‑silver alloy mesoporous nanospheres (PdAg MNs) via a micelle-directed approach. Compared to Pd MNs, the PdAg MNs showed enhanced performance, achieving a Faradaic efficiency (FE) for PG of 50.7% and 87.6% selectivity at 1.15 V. During reaction, surface Pd transforms into Pd 2+ /Pd 4+ species, boosting OH binding energy and optimizing surface OH coverage. This promotes the *OH-mediated consecutive hydroxylation pathway. Density functional theory (DFT) studies elucidated that Ag incorporation optimizes the adsorption/desorption energetics of propylene and PG, accelerates water activation kinetics and the *OH generation rate, and maintains a high *OH surface coverage on the PdAg MNs. This work achieves efficient PG synthesis by promoting the consecutive hydroxylation pathway through regulation of the *OH coverage during propylene oxidation, providing deeper mechanistic understanding into olefin oxidation.