Researchers have developed a new biochar material derived from marine microalgae that can detect hydrogen peroxide rapidly, sensitively, and without the need for enzymes. The discovery could support applications ranging from medical diagnostics to environmental monitoring and food safety.
Hydrogen peroxide plays a dual role in modern society. It is widely used in healthcare, biotechnology, and industry, yet excessive levels can signal oxidative stress in biological systems or contamination in food and water. Detecting hydrogen peroxide quickly and accurately therefore remains a major analytical challenge.
In a new study, scientists created a nickel-enriched biochar by cultivating marine microalgae in a nickel-containing growth medium and then converting the biomass into carbon through controlled pyrolysis. The resulting material contains uniformly distributed nickel nanoparticles embedded in a porous carbon structure, which significantly enhances its electrochemical performance.
"We wanted to design a sustainable sensor material using biological resources rather than fossil-based carbons," said the study's corresponding author. "Microalgae provide an ideal platform because they grow rapidly, accumulate metals naturally, and can be converted into functional carbon materials."
The research team demonstrated that electrodes coated with the new biochar could detect hydrogen peroxide at concentrations as low as 0.39 micromolar, with response times of about two seconds. The sensor also performed well under physiological pH conditions and maintained high recovery rates in complex samples such as seawater, milk, and juice.
Unlike many conventional sensors, the system does not rely on enzymes, which can degrade quickly or require strict environmental control. Instead, the nickel atoms embedded in the biochar act as catalytic centers that promote the electrochemical oxidation of hydrogen peroxide. The uniform distribution of these catalytic sites improves sensitivity while maintaining stability over repeated measurements.
"Our results show that biological metal enrichment during growth leads to much better catalytic performance than simply mixing metals with carbon afterward," the authors noted. "This approach opens a new route for designing functional biochar materials with controlled metal distribution."
Beyond hydrogen peroxide detection, the researchers suggest the strategy could be adapted to create other biochar-based sensing materials by incorporating different metals or biological feedstocks. Because the process uses naturally cultivated microalgae and relatively inexpensive metals, it may offer a scalable and environmentally friendly alternative to traditional nanomaterial synthesis.
The team believes the work could contribute to future biosensors for medical diagnostics, environmental monitoring, and industrial quality control. With further development, such sensors may be integrated into portable analytical devices or smart monitoring systems.
"Our goal is to bridge sustainable materials science with practical sensing technologies," the researchers said. "By combining biology with electrochemistry, we can create new materials that are both high-performance and environmentally responsible."
The study highlights how renewable biological resources can be transformed into advanced functional materials, pointing toward greener approaches for next-generation sensor technologies.
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Journal Reference: Gan, H., Tang, Y., Yang, S. et al. A novel biochar from Ni-fed picochlorum eukaryotum for use as a high-performance enzyme-free electrochemical sensor of hydrogen peroxide. Biochar 8, 17 (2026).
https://doi.org/10.1007/s42773-025-00529-0
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About Biochar
Biochar (e-ISSN: 2524-7867) is the first journal dedicated exclusively to biochar research, spanning agronomy, environmental science, and materials science. It publishes original studies on biochar production, processing, and applications—such as bioenergy, environmental remediation, soil enhancement, climate mitigation, water treatment, and sustainability analysis. The journal serves as an innovative and professional platform for global researchers to share advances in this rapidly expanding field.
