The use of concentrated solar energy in processing ceramic materials is an attractive route to obtain these materials with low CO₂ emissions. In this work, nanostructures of monoclinic zirconia (m-ZrO₂) were obtained using concentrated solar energy provided by the IER-UNAM solar furnace as a heat source. In the first stage of the process, a Zr/O/C complex was obtained by sol-gel method at a temperature of 120 °C using zirconium n-propoxide and sorbitol as precursors reagents. This complex was used in a second stage to obtain m-ZrO₂ by heating it at a temperature of 1200 °C for one hour in air atmosphere. This last stage was performed in a solar furnace. Samples were analyzed by characterization techniques: FT-IR, TGA/DSC, XRD, TEM, and SEM confirming the formation of nanostructures of zirconia in monoclinic phase.

The growing global population has resulted in a higher demand for energy, leading researchers to prioritize the development of alternative energy sources and the improvement of current technologies. Nanofluids (NFs) are a promising method for enhancing heat transfer and efficiently utilizing solar thermal energy. This study describes the preparation of four NFs: two mono NFs of SiC and HfC containing nanoparticle concentrations ranging from 0.10–1.0 wt.%. Moreover, two hybrid NFs were synthesized within the same concentration range (0.10–1.0 wt.%) of SiC-HfC nanocomposites in proportions of 60 wt.% SiC-40 wt.% HfC and 40 wt.% SiC-60 wt.% HfC, all dispersed in a mixture of ethylene glycol (EG) and distilled water (50EG-50H₂O). The materials were synthesized by carbothermal reduction, and the NFs were prepared using the two-step method. The NFs showed stable dispersion, with HfC and 40SiC-60HfC systems exhibiting the higher zeta potential (ζ) values. Viscosity remained largely unaffected by particle addition. The thermal diffusivity of the NFs was measured by the thermal lens spectroscopy (TLS) technique using 1:20 diluted samples. The hybrid nanofluid 40SiC-60HfC improved diffusivity by 66.93%, presenting a synergistic effect in its performance, highlighting its potential in clean energy systems.