2D Ni-organic frameworks decorated carbon nanotubes encapsulated Ni nanoparticles for robust CN and HO bonds cleavage

• Published in: Journal of colloid and interface science Vol. 652; pp. 41 - 49
• Main Authors: Xie, Yuhua, Xiong, Tiantian, Li, Chen, Shi, Han, Zhou, Cong, Luo, Fang, Yang, Zehui
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 15.12.2023
• Subjects: Hydrogen evolution reaction; Ni-MOF; Synergistic effect; Urea oxidation reaction; Hydrogen evolution reaction; Urea oxidation reaction; Synergistic effect; Ni-MOF
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2023.08.063

[Display omitted] •Nitrogen doped carbon nanotubes with encapsulated Ni nanoparticles have been coated with Ni-MOF.•Ni-MOF@Ni-NCNT exhibited a superior UOR activity due to its lower binding strength with CO2 and more active sites.•HER-UOR system requires only 1.33 V to reach 10 mA cm−2 for Ni-MOF@Ni-NCNT, 270 mV lower than Pt/C-IrO2. In this work, we report a robust bifunctional electrocatalyst composed of 2D Ni- organic frameworks (Ni-MOF) and nitrogen doped carbon nanotubes encapsulated Ni nanoparticles (Ni-MOF@Ni-NCNT) for CN and HO bonds dissociation. Due to the presence of Ni-NCNT, adsorption of OH– species is enhanced and CO2 binding strength is simultaneously weakened leading to a boosted urea oxidation reaction performance reflected by decrement in potential at 100 mA cm−2 by 69 mV. The loosened binding strength with CO2 specie is highlighted by in-situ electrochemical impedance spectroscopy (EIS) test and DFT calculation. Moreover, the alkaline hydrogen evolution reaction (HER) performance of Ni-MOF@Ni-NCNT is better than Ni-MOF and Ni-NCNT evidenced by the overpotential at 50 mA cm−2 decreased by 224 mV and 900 mV ascribed to the synergistic effect, in which Ni-MOF, Ni nanoparticles and Ni-Nx-C facilitates water adsorption, dissociation and adsorption/combination of hydrogen ions, respectively. The assembled HER- urea oxidation reaction (UOR) system requires only 1.33 V to reach 10 mA cm−2, 70 mV lower than water splitting driven by Pt/C-IrO2.