The sluggish kinetics and high overpotential associated with OER have long hindered its efficiency, limiting the potential of renewable hydrogen production. In response to these challenges, the team developed a novel NiO/Fe3O4@LCFs electrocatalyst, integrating nickel and iron oxides with lignin-derived carbon fibers.
The OER is a key reaction in water splitting processes and metal-air batteries, but its efficiency is currently limited by the high overpotential and slow kinetics. Traditionally, noble-metal oxides like IrO2 and RuO2 have been used as catalysts, but their scarcity and high cost, combined with their tendency to degrade at industrial current densities, pose significant challenges. As a result, researchers have turned to base-metal oxides such as nickel (Ni) and iron (Fe) oxides. While these materials show promise, they often suffer from issues such as low conductivity and poor structural stability. In response, integrating these transition-metal oxides with highly conductive carbon supports, especially those derived from renewable resources, has emerged as a promising solution.
A study (DOI:10.48130/bchax-0025-0011) published in Biochar X on 27 November 2025 by Yanlin Qin’s & Xueqing Qiu’s team, Guangdong University of Technology, not only improves the OER performance but does so by utilizing a renewable and cost-effective biomass resource, providing a scalable and sustainable solution to enhance the efficiency of alkaline water electrolysis.
The NiO/Fe3O4@LCFs catalyst was synthesized through a multi-step process starting with electrospinning a precursor solution containing lignin, polyacrylonitrile (PAN), and metal ions (Ni and Fe). This formed a three-dimensional fiber membrane, which was pre-oxidized to stabilize its structure before undergoing carbonization to create the final catalyst. The resulting catalyst featured NiO and Fe3O4 nanoparticles embedded within a nitrogen-doped carbon fiber (LCFs) matrix. Structural analysis using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that the metal oxides were uniformly distributed within the carbon fiber network, with the NiO/Fe3O4 particles embedded in the fibers in a stable, well-dispersed manner. High-resolution TEM images confirmed the formation of a heterojunction between NiO and Fe3O4, which is expected to enhance electron transfer during the oxygen evolution reaction (OER). Energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) further validated the uniform elemental distribution and the presence of in situ nitrogen doping, which enhanced the conductivity of the catalyst. X-ray diffraction (XRD) and Raman spectroscopy analyses showed the catalyst’s robust crystalline structure and high degree of graphitization, both of which contribute to its excellent conductivity and stability. Electrochemical testing demonstrated that the NiO/Fe3O4@LCFs catalyst exhibited superior OER performance, with a low overpotential of 250 mV at 10 mA cm–2 and a Tafel slope of 138 mV dec–1, indicating fast reaction kinetics. Additionally, the catalyst maintained excellent stability, showing minimal degradation after 50 hours of operation. The study highlights the synergistic effects of the metal oxides and the nitrogen-doped carbon fiber support, providing a scalable and efficient solution for water-splitting applications.
This research opens the door to the use of lignin, a low-cost, renewable biomass, in the development of high-performance electrocatalysts. The NiO/Fe3O4@LCFs catalyst demonstrates not only enhanced efficiency for the OER but also excellent durability, making it a promising candidate for large-scale water splitting applications. The use of lignin as a precursor offers a sustainable route to fabricate electrocatalysts, aligning with circular economy principles and providing a new method for valorizing lignin waste from the paper and biorefinery industries.
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References
DOI
10.48130/bchax-0025-0011
Original Source URL
https://doi.org/10.48130/bchax-0025-0011
Funding information
This work was funded by the National Natural Science Foundation of China (22422802, U23A6005, and 22408057).
About Biochar X
Biochar X is an open access, online-only journal aims to transcend traditional disciplinary boundaries by providing a multidisciplinary platform for the exchange of cutting-edge research in both fundamental and applied aspects of biochar. The journal is dedicated to supporting the global biochar research community by offering an innovative, efficient, and professional outlet for sharing new findings and perspectives. Its core focus lies in the discovery of novel insights and the development of emerging applications in the rapidly growing field of biochar science.