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Updated: Feb 6, 2026

Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating
Published on: April 12, 2018
Combination of electronic structure regulation and controllable phase transition engineering for urea-assisted
Tongxue Zhang1, Mengmeng Jin2, Jingming Bao3
1School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, PR China.
Abstract:
Utilizing the thermodynamically favorable urea oxidation reaction (UOR) as a substitute for the oxygen evolution reaction (OER) in conventional water electrolysis offers a viable method for wastewater treatment and energy-efficient hydrogen generation. A series of samples with abundant cation vacancies were synthesized via a hydrothermal method followed by alkaline etching. The electronic and crystal structures of the catalysts were simultaneously modulated by precisely tuning the concentration of the vacancy-inducing medium. The β-type NiCov 1:1-2% with abundant cation vacancies demonstrates superior UOR activity, with just 1.31 and 1.35 V vs. RHE needed to reach current densities of 10 and 100 mA cm-2, respectively. Characterization experiments indicate that the optimization of electronic structure through cation vacancies and distinctive multilayered flake morphology can enhance the number of active sites and improve mass transfer efficiency. A series of in situ measurements further corroborate the rapid yet moderate phase transitions of NiCov 1:1-2%. Theoretical calculations demonstrate that the introduction of cation vacancies optimizes the balance between reactant adsorption and product desorption, leading to a reduced Gibbs free energy barrier for the rate-determining step of UOR. This study offers valuable guidance for the rational design of efficient and versatile catalysts for small-molecule oxidation reactions.
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