Enhancing the Performance of Solar Thermal Collectors Using Nanocomposite (Nitrogen-Doped Carbon Quantum Dots Combined with Zinc Titanate) Extracted from Malva Sylvestris
نویسندگان
1 Department of Mechanical Engineering, College of Engineering, University of Misan, Maysan, Iraq
2 Department of Pharmaceutical Chemistry, College of Pharmacy, University of Misan, Maysan, Iraq
3 Department of Mechanical Engineering, College of Engineering, University of Misan, Maysan, Iraq
doi
10.22052/JNS.2025.04.073چکیده
Improving efficiency of solar thermal collectors using the nitrogen-doped carbon quantum dots/Zn₂Ti₃O₈ (N-CQDs/ZTO) nanocomposites extracted from Malva sylvestris is promising for enhancing the thermal sustainability. This nanocomposite is considered a natural source of carbon and nitrogen used as a component in a spectrally selective solar absorber coating. The N-CQDs/ZTO, which made them better at absorbing visible spectrum and moving charge carriers. Transmission electron microscopy (TEM) confirmed the consistent distribution of N-CQDs on the Zn₂Ti₃O₈ surface. Diffuse reflectance spectroscopy (DRS) showed a significant red shift and a smaller band gap (2.73 eV) when compared to pristine Zn₂Ti₃O₈ (3.36 eV). Photoluminescence (PL) studies showed better electron-hole separation efficiency. The N-CQDs/ZTO nanocomposite demonstrated remarkable photocatalytic degradation capacity for methylene blue (MB) after 120 minutes of exposure to visible light, achieving a 91.7% elimination rate. Throughout a sequence of five cycles, the examination on the solution pH, catalyst loading and oxidant concentration reveals that the thermal performance of solar collector would be more active and stable. The enhancement of the solar thermal collector with nanocomposite showed that it could work better as a photocatalyst, which means it could be used in hybrid solar thermal–photocatalytic systems. The N-CQDs/ZTO nanocomposite is a good candidate for use in solar thermal collectors and other renewable energy conversion systems because its optical and thermal properties work together to improve the overall efficiency of solar energy use.
