Stabilized Bi(III) Sites Direct *NH ₂ OH Pathway for Efficient Cyclohexanone Oxime Electrosynthesis

Abstract

ABSTRACT Coupling electrocatalytic nitrite reduction reaction (NO 2 − RR) with cyclohexanone conversion enables a sustainable route to cyclohexanone oxime (CHO) electrosynthesis, a key feedstock for the nylon‐6 industry. However, this approach is fundamentally constrained by the difficulty of sustaining selective *NH 2 OH intermediate formation. Here, we reveal for the first time that the Bi(III) sites can enable the catalytic system to efficiently follow the *NH 2 OH pathway, avoiding the undesired *N pathway. Accordingly, a BiPO 4 /SiO x interface was designed in which amorphous SiO x functions as an electron‐buffer to stabilize Bi(III) active sites. As a result, the BiPO 4 /SiO x catalyst exhibits a high faradaic efficiency (FE CHO ) of 77.0 ± 3.4% and a CHO yield rate of 0.64 ± 0.01 mmol h −1 cm −2 , surpassing all previously reported catalysts in H‐cellMoreover, the BiPO 4 /SiO x catalyst delivers a nearly 100% carbon and nitrogen selectivity to CHO and retains 91.8% of its initial efficiency after extended cycling, substantially outperforming pristine BiPO 4 . Combined experimental and theoretical analyses reveal that the stabilized Bi(III) site suppresses the formation of surface K + H 2 O, effectively suppressing competing hydrogen evolution and over hydrogenation, thereby enabling efficient CHO electrosynthesis.