Fe2O3-CeO2/PMMA nanocomposite-enhanced solar box cooker with efficient photothermal conversion and extended thermal storage

• Fe₂O₃–CeO₂/PMMA nanocomposites developed for enhanced solar photothermal conversion. • Nanocomposites exhibited broadened solar absorption and reduced optical bandgap. • SBC stagnation temperature increased up to 148.16°C at 4.2 wt% loading. • Thermal efficiency improved by 69.4% compared to the pure system. • Cooking time reduced to 49 min for rice and 15 min for pasta. Researchers have designed and manufactured a new type of nanocomposite material using plastic, iron, and cerium nanoparticles in order to increase the efficiency of solar box cookers (SBCs) by converting solar energy into thermal energy, and explain how the nanocomposites use the ability of solar light to be absorbed at various wavelengths (or broadband) to improve the overall efficiency of an SBC. The authors created a new hybrid nanocomposite by developing a way to embed ceria (CeO₂) and hematite (Fe₂O₃) nanoparticles into a matrix of poly(methyl methacrylate) (PMMA) so that both can combine to create a new material with a broader wavelength absorbance range and therefore better thermal energy conversion characteristics. The authors also performed chemical-mechanical polishing (CMP) analysis to determine the photothermal conversion parameters and surface smoothness of the hybrid nanoparticles. The results from the CMP analysis showed that the hybrid nanoparticles outperformed either PMMA or ceria when tested separately. The authors indicate that the reason for their improved performance was due to the unique properties provided by each of the materials working together (PMMA core plus ceria shell) acting like micro-sized fixed abrasives. Optical properties showed that 4.2% wt. loading of Fe₂O₃-CeO₂/PMMA nanostructures have increased their optical absorption by 33.5% and decreased their transmission at 240 nm by 53.7%. The nanocomposite has good potential for photonic uses. They have also been observed to have greater absorption of solar energy, with a decrease in the band gap from 4.14 eV (pure SBC) to 2.08 eV (4.2% wt. SBC). Increasing the concentration of the nanocomposites increased the stagnation efficiency of the SBC (F 1 ) with the temperature being 88.88°C for pure SBC and 148.16°C for 4.2% wt. SBC. Peak absorber temperature also increased from 81.16°C to 131.8°C. The final resulted for thermal efficiency also increased by 69.4%. The 4.2% wt. optimized nanocomposite has vastly improved cooking time. For example, it took 15 minutes to cook pasta, while 49 minutes to cook rice compared to 32 minutes and about 106 minutes, respectively, for all of the lower concentrations. These data suggest that Fe₂O₃-CeO₂/PMMA nanocomposites can be an efficient way to improve the performance of SBCs through a combination of broad-band light absorption, increased thermal conversion, and high cooking efficiency.