Modulating the Electronic Structure of Ni/NiO Nanocomposite with High‐Valence Mo Doping for Energy‐Saving Hydrogen Production via Boosting Urea Oxidation Kinetics

Abstract

Electrocatalytic urea oxidation reaction (UOR) has emerged as a promising alternative to the anodic oxygen evolution reaction (OER) in water electrolysis. However, UOR faces challenges like slow kinetics, high energy barriers, and a complex mechanism, necessitating the development of efficient electrocatalysts. Herein, a rapid method is proposed for synthesizing Mo‐doped Ni/NiO (Ni/MNO) nanocomposite as a highly effective UOR electrocatalyst. Mo doping oxidizes Ni2+ to Ni3+, creating abundant active sites for UOR. The Ni/MNO catalyst exhibits remarkable activity for both OER and UOR due to Mo doping, structural modulation, increased active sites, and the presence of Ni3+ ions. Optimized Ni/MNO‐10 shows a low OER overpotential of 280 mV and a UOR working potential of 1.37 V versus reversible hydrogen electrode at 10 mA cm−2, with exceptional stability over 12 h of continuous electrolysis. Notably, urea‐assisted water splitting requires only 1.45 V for 10 mA cm−2, significantly less than the overall water splitting voltage (1.65 V), indicating energy‐efficient hydrogen production. Moreover, the Ni/MNO catalyst exhibits outstanding long‐term stability. This work presents a rapid and effective approach to synthesizing cost‐effective and efficient electrocatalysts for clean energy production and wastewater treatment.

Electronic Structure Modulation Via Iron-Incorporated NiO to Boost Urea Oxidation/Oxygen Evolution Reaction

“…Doping high-valence heterogeneous atoms, such as Mo, W, V, Fe, etc., represents a competent approach for modulating the electronic structure of Ni site in catalytic processes. − To date, hydrothermal or high-temperature techniques have been employed to obtain highly active heteroatom-doped electrocatalysts. Nevertheless, these approaches are associated with intricate experimental procedures, prolonged reaction times, and low product yields.…”