In a recent article published in the journal Scientific Reports, researchers introduced a novel and eco-friendly method for synthesizing boron carbonitride (BCN) nanosheets from biomass, which serve as photocatalysts for hydrogen production.
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Background
Hydrogen is a clean and renewable energy source produced through water splitting, a process that uses light to break water molecules into hydrogen and oxygen. Efficient photocatalysts are essential for this process as they absorb light and generate electron-hole pairs to drive the reaction. Most existing photocatalysts are based on metal or metal oxide semiconductors, which suffer from high costs, low abundance, and environmental toxicity.
BCN is a promising metal-free semiconductor that has the potential to be used as a photocatalyst for hydrogen production. Its unique electronic and structural properties facilitate carbon dioxide (CO2) fixation and water splitting. However, synthesizing BCN usually requires high temperature and pressure and expensive and scarce carbon sources like graphite or acetylene. Bulk BCN often has a low surface area and high defect density, limiting its effectiveness as a photocatalyst.
About the Research
In this paper, the authors developed an eco-friendly and sustainable method to synthesize BCN nanosheets from biomass, which are abundant and renewable carbon sources derived from plants or animals. They combined biomasses such as amylum, sucrose, maltose, and fructose as carbon precursors with urea and boric acid. The mixture was then heated in a tube furnace under an ammonia atmosphere to produce BCN nanosheets with diverse compositions and structures.
The researchers compared these BCN nanosheets' morphology, composition, structure, and performance against bulk BCN and BCN materials derived from different carbon sources. They used a range of characterization techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, electrochemical impedance spectroscopy (EIS), and transient photocurrent response.
The BCN nanosheets' photocatalytic hydrogen production capabilities were assessed under visible light irradiation, employing Pt nanoparticles as co-catalysts and triethanolamine (TEOA) as sacrificial reagents. The performance of these BCN nanosheets in photocatalytic CO2 reduction was also evaluated under similar conditions.
Research Findings
The outcomes showed that the BCN nanosheets synthesized from amylum (BCN-A) exhibited the best morphology, composition, structure, and performance compared to all other BCN materials. The BCN-A nanosheets featured a two-dimensional (2D) sheet structure, a high surface area of 205 m²/g, a low band gap of 2.77 eV, high crystallinity, low defect density, and a uniform boron, carbon, and nitrogen distribution.
These BCN-A nanosheets achieved the highest photocatalytic hydrogen evolution rate (HER) of 110 μmol/h/g, 9.1 times greater than that of bulk BCN. They outperformed the performance of other BCN materials reported in the literature. They also showed a high photocatalytic CO2 reduction rate of 0.8 0.8 μmol/h/g, higher than other BCN materials.
The authors noted that the BCN-A nanosheets excel in photocatalytic performance due to their unique electrical properties, flexible 2D structure, high crystallinity, and large surface area. These features efficiently separated and transferred photoexcited electron-hole pairs. The BCN-A nanosheets were very stable and could be reused, maintaining their structure and performance even after 16 hours of continuous use.
Applications
This research demonstrated that biomass-derived BCN nanosheets are effective photocatalysts for hydrogen production and CO2 reduction. These processes are crucial for converting solar energy into chemical energy and reducing greenhouse gas emissions.
The study presented an eco-friendly and efficient method to synthesize BCN nanosheets from biomass, a sustainable and cost-effective carbon source. It also highlighted that the type and composition of biomass can influence the properties and performance of BCN nanosheets.
Conclusion
In summary, BCN nanosheets synthesized from biomass showed enhanced photocatalytic performance for hydrogen production and CO2 reduction.
The authors emphasized that these biomass-based BCN materials offer a greener and more efficient path to hydrogen energy, supporting the global shift toward renewable energy solutions. They recommended exploring the synthesis and use of BCN nanosheets from various biomass sources and designing them with specific properties and functions.
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Source:
Luo, Z., Chen, J., Fang, Y. et al. Synthesis of borocarbonitride nanosheets from biomass for enhanced charge separation and hydrogen production. Sci Rep 14, 14443 (2024). DOI: 10.1038/s41598-024-65380-y, https://www.nature.com/articles/s41598-024-65380-y