Superior electrocatalytic activity of cobalt–nickel oxide nanoneedle films toward oxygen evolution reaction in alkaline electrolyte and alkaline simulated seawater electrolyte
- 1Institute of Materials Science, Vietnam Academy of Science and Technology Hanoi Vietnam
- 2Division of Physics and Semiconductor Science, Dongguk University Seoul 04620 Republic of Korea
Abstract
Seawater splitting is a promising technology for clean energy production, as it directly uses abundant seawater to generate hydrogen fuel. In this process, the oxygen evolution reaction (OER) is the key half reaction, and the development of efficient, stable catalysts is important to enhance energy efficiency, reduce overpotentials and for long-term stability in chloride-containing electrolytes. In this research, cobalt–nickel oxide nanoneedle films were synthesized on Ni foam with different Co/Ni precursor ratios (2 : 1, 1 : 1, 1 : 2). The oxide films were prepared by thermal treatment of cobalt–nickel hydroxycarbonate precursors prepared via a hydrothermal method. The resulting films were characterized by using scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). Among them, CoNiO-1 (Co/Ni = 2 : 1) exhibited superior OER performance, achieving low overpotentials of 480 mV at 100 mA cm−2 and 655 mV at a high current density of 300 mA cm−2 in alkaline electrolyte, and 475 mV at 100 mA cm−2 in alkaline simulated seawater, while displaying the lowest Tafel slope among all tested samples. Furthermore, CoNiO-1 demonstrated long-term stability at a high current density of 100 mA cm−2 for 24 hours in both alkaline electrolyte and alkaline simulated seawater. The crystal structure and surface morphology were well retained after the durability test. Additionally, the N,N-diethyl-1,4-phenylenediamine (DPD) colorimetric method confirmed the absence of the chlorine evolution reaction. The CoNiO-1/NF electrode also exhibited a faradaic efficiency approaching the theoretical limit during the OER in alkaline simulated seawater, reflecting its high selectivity for oxygen evolution. These results highlight its potential as an efficient OER electrocatalyst for seawater-splitting applications.
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BibTeX
@article{bui2026superior,
title = {{Superior electrocatalytic activity of cobalt–nickel oxide nanoneedle films toward oxygen evolution reaction in alkaline electrolyte and alkaline simulated seawater electrolyte}},
author = {Hoa Thi Bui and Pham Hong Hanh and Nguyen Duc Lam and Le Thi Hong Phong and Do Chi Linh and Doan Dinh Phuong and Nabeen K. Shrestha},
journal = {RSC Advances},
year = {2026},
month = oct,
doi = {10.1039/d6ra04138h},
url = {https://doi.org/10.1039/d6ra04138h},
note = {CC BY-NC 3.0},
}
RIS
TY - JOUR
TI - Superior electrocatalytic activity of cobalt–nickel oxide nanoneedle films toward oxygen evolution reaction in alkaline electrolyte and alkaline simulated seawater electrolyte
AU - Hoa Thi Bui
AU - Pham Hong Hanh
AU - Nguyen Duc Lam
AU - Le Thi Hong Phong
AU - Do Chi Linh
AU - Doan Dinh Phuong
AU - Nabeen K. Shrestha
PY - 2026
DA - 2026/10/26
JO - RSC Advances
DO - 10.1039/d6ra04138h
UR - https://doi.org/10.1039/d6ra04138h
AB - Seawater splitting is a promising technology for clean energy production, as it directly uses abundant seawater to generate hydrogen fuel. In this process, the oxygen evolution reaction (OER) is the key half reaction, and the development of efficient, stable catalysts is important to enhance energy efficiency, reduce overpotentials and for long-term stability in chloride-containing electrolytes. In this research, cobalt–nickel oxide nanoneedle films were synthesized on Ni foam with different Co/Ni precursor ratios (2 : 1, 1 : 1, 1 : 2). The oxide films were prepared by thermal treatment of cobalt–nickel hydroxycarbonate precursors prepared via a hydrothermal method. The resulting films were characterized by using scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). Among them, CoNiO-1 (Co/Ni = 2 : 1) exhibited superior OER performance, achieving low overpotentials of 480 mV at 100 mA cm−2 and 655 mV at a high current density of 300 mA cm−2 in alkaline electrolyte, and 475 mV at 100 mA cm−2 in alkaline simulated seawater, while displaying the lowest Tafel slope among all tested samples. Furthermore, CoNiO-1 demonstrated long-term stability at a high current density of 100 mA cm−2 for 24 hours in both alkaline electrolyte and alkaline simulated seawater. The crystal structure and surface morphology were well retained after the durability test. Additionally, the N,N-diethyl-1,4-phenylenediamine (DPD) colorimetric method confirmed the absence of the chlorine evolution reaction. The CoNiO-1/NF electrode also exhibited a faradaic efficiency approaching the theoretical limit during the OER in alkaline simulated seawater, reflecting its high selectivity for oxygen evolution. These results highlight its potential as an efficient OER electrocatalyst for seawater-splitting applications.
SN - 2046-2069
ER -