Regulating the Electronic Structure of Tungsten Carbide‐Induced Co(OH) <sub>2</sub> for Efficient Water and Urea Electrolysis in Hydrogen Production from Urea‐Containing Water
Ranjith Kumar Dharman, Pandian Mannu, Athibala Mariappan, Chung‐Li Dong, Tae Hwan Oh
Abstract
Abstract Urea oxidation reaction (UOR) is considered a capable method for simultaneously producing hydrogen and treating urea‐rich wastewater. The development of well‐designed, high‐performance electrocatalysts is crucial for efficient urea oxidation. In this study, a tungsten carbide (WC) and Co(OH) 2 nanocomposite (WC@Co(OH) 2 ) is synthesized through a simple hydrothermal process for electrocatalytic UOR performance. X‐ray absorption spectroscopy revealed that WC@Co(OH) 2 ‐2 exhibited higher levels of high‐spin Co 3+ electronic states compared to pristine Co(OH) 2 . The optimized WC@Co(OH) 2 electrocatalysts showed remarkable activity in the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and UOR, with potentials of 0.152, 1.475, and 1.38 V, @ 10 mA cm −2 , respectively. The WC@Co(OH) 2 ‐2 catalyst also exhibited a high turnover frequency of 31.2 s −1 . Moreover, an overall urea electrolysis system constructed with the prepared WC@Co(OH) 2 , attained 1.55 V at 10 mA cm −2 , which is 0.21 V lower than the potential required for overall water splitting. In situ Raman result revealed the quick reconstruction of WC 1‐x @Co(OH) 2 , where tungsten species infiltrate into CoOOH, forming a restored WC 1‐x @CoOOH layer that serves as the active species for water splitting. Furthermore, the WC@Co(OH) 2 ‐2 exhibited a high Faradaic efficiency of 92.18% and exceptional durability. This work broadens the UOR electrocatalyst and contributes the advancement of energy‐efficient hydrogen production technologies.