Enhanced water electrolysis activity by CoNi-LDH/Co -nitrogen-doped carbon heterostructure with dual catalytic active sites

• Published in: Electrochimica acta Vol. 444; p. 141956
• Main Authors: Sang, Yan, Guo, Zixuan, Li, Guohong, Xue, Yingying, Xue, Jingwei
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 10.03.2023
• Subjects: Cooperative effects; Electrochemistry; Layered double hydroxides; Metal-organic frameworks; Water splitting; Electrochemistry; Water splitting; Cooperative effects; Metal-organic frameworks; Layered double hydroxides
• ISSN: 0013-4686
• DOI: 10.1016/j.electacta.2023.141956

•The CoNi-LDH/Co@NC was constructed by calcination and solvothermal method.•The CoNi-LDH/Co@NC accelerates the charge transfer.•The CoNi-LDH/Co@NC catalyst exhibits remarkable catalytic activity for water splitting.•The CoNi-LDH/Co@NC exhibits an overpotential of 75 mV for HER and 207  mV for OER at 10 mA cm−2. The study and development of bifunctional non-precious metal catalysts with excellent oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) electrocatalytic activities are particularly important and challenging for electrocatalytic total water splitting. Here, we report a non-precious material constructed by growing cobalt-nickel double hydroxides on ZIF-derived Co nanoparticles and nitrogen-doped carbon framework (CoNi-LDH/Co@NC), which exhibits excellent electrocatalytic performances for both OER and HER in alkaline media. When used as OER and HER electrocatalysts, CoNi-LDH/Co@NC only needs 359 mV and 187 mV overpotentials at a current density of 100 mA cm−2, respectively. Surprisingly, using CoNi-LDH/Co@NC as both cathode and anode for a two-electrode water splitting system, a small battery voltage of 1.51 V is required at the current density of 10 mA cm−2, and the current density remained stable for 20 h without any obvious attenuation. This opens up new possibilities for further exploration of non-precious metal electrocatalysts for water splitting. CoNi-LDH/Co@NC materials retaining the original ZIF-67 configuration were successfully synthesized by a facile calcination assisted solvothermal methods. Due to the synergistic effect of CoNi-LDH and Co@NC, the N-doping, high electrical conductivity and the large specific surface area of NC, the as-obtained CoNi-LDH/Co@NC can be used as an efficient and stable dual-function electrocatalyst to achieve efficient all-water splitting. [Display omitted]