High-valence molybdenum-induced amorphization engineering for porous MoOx/NiO/NF electrodes toward efficient 1-propanol oxidation to propionic acid

Abstract

Using high-valence metals typically induces lattice distortion and suppresses crystal growth in nickel-based catalysts, leading to the formation of defect-rich amorphous structures. These isotropic amorphous catalysts, characterized by a high density of accessible active sites, hold great promise for the selective oxidation of alcohols to value-added carboxylic acids under mild conditions. Herein, a defect-rich amorphous NiO phase induced high-valence Mo doped is formed via a sequential hydrothermal and air-pyrolysis strategy for the selective oxidation of 1-propanol to propionic acid. Mo doping effectively inhibits the crystallization of, inducing while simultaneously optimizing the electronic structure of the nickel centers. This structural modulation facilitates the in situ generation of the key active species, nickel oxyhydroxide (NiOOH). Consequently, the as-prepared MoOx/NiO/NF electrode achieves a remarkable Faradaic efficiency of 91.94% for propionic acid with a high production rate of 9.98 mol h−1 m−2 at 1.5 V vs. RHE. Furthermore, the catalyst exhibits superior durability, maintaining 93.68% of its initial current density after a 12-h chronoamperometric test, significantly outperforming the crystalline Ni(OH)2/NF benchmark (77.72%). This work provides a robust strategy for the rational design of high-performance amorphous electrocatalysts and advances the green synthesis of carboxylic acids via electrochemical oxidation.