Spontaneous Interfacial Dehydrogenation Enables Selective Electrooxidation of 1,2‐Butanediol to 1‐Hydroxy‐2‐butanone

Selective electrooxidation of 1,2‐butanediol (1,2‐BDO) to 1‐hydroxy‐2‐butanone (1‐HB) offers an attractive strategy for upgrading vicinal diols into value‐added α‐hydroxy ketones but remains challenged by poor regioselectivity and the rapid base‐induced transformation of 1‐HB under alkaline conditions. Herein, we report a spontaneous interfacial dehydrogenation process on PtPdNi/NF that proceeds through coupled α‐C─H and O─H activation of the secondary alcohol in 1,2‐BDO, inducing pronounced H 2 evolution under open‐circuit conditions in alkaline media. This spontaneous dehydrogenation is self‐limiting and ceases after a finite period owing to the absence of continuous electron extraction. Upon applying an external potential, sustained electron extraction maintains the dehydrogenation process, delivering an ultrahigh current density of 800 mA cm −2 at only 0.56 V versus RHE. Furthermore, by integrating a 25 cm 2 single‐pass flow cell with in‐line neutralization, the exposure of generated 1‐HB to the alkaline electrolyte is minimized, thereby suppressing its base‐induced transformation while simultaneously alleviating catalyst deactivation caused by the accumulation of products and product accumulation, achieving a Faradaic efficiency of 87% toward 1‐HB at 60°C under the investigated flow‐cell conditions. This work establishes an integrated catalyst–reactor strategy that couples spontaneous interfacial dehydrogenation with rapid product extraction, enabling highly efficient and selective electrooxidative upgrading of vicinal diols.