Experimental Investigation of SiO₂-CeO₂ Hybrid Nanoparticles for Enhancing Thermal Energy Storage in Beeswax-Based Phase Change Material

This study explores enhanced thermal performance in beeswax-based phase change materials (PCMs) using SiO₂-CeO₂ hybrid nanoparticles. Samples with different nanoparticle concentrations (0.5, 1.0, and 2.0 wt%) were characterized for thermal conductivity, stability, and phase change behavior. Differential Scanning Calorimetry (DSC) showed reduced supercooling, with the 1.0 wt% sample (HN-BB-BW-1.0) achieving a 55% reduction from 9.3°C to 4.2°C while maintaining a latent heat capacity of 168.5 J/g. Thermogravimetric analysis (TGA) indicated a 10% increase in thermal stability for the 1.0 wt% sample, with a degradation temperature of 220°C compared to 200°C for the control. In thermal conductivity tests, HN-BB-BW-1.0 reached 0.40 W/m·K, a 66.67% improvement over the control (0.24 W/m·K). The 2.0 wt% sample (HN-BB-BW-2.0) exhibited the highest conductivity enhancement at 75%, but it had stability problems and saturation of latent heat capacity due to nanoparticle agglomeration. The 1.0 wt% concentration was optimal, balancing thermal stability, thermal conductivity, and energy storage capacity. The findings show that nanoparticles of SiO₂-CeO₂ increased the thermal efficiency of nano-enhanced bio-based phase change materials for use in low-temperature thermal energy storage and solar thermal systems.