Construction and photothermal synergistic mechanism of Ti₃C₂T_x/HCS solvent-free nanofluids in aqueous dispersion

Regarding the backdrop of increasing global energy constraints, solar energy has garnered significant attention due to its prominent advantages, such as abundance and cleanliness. Among various solar technologies, solar-thermal utilization, as one of the most direct and efficient pathways, has become a research focus. Solar collectors based on nanofluids can further enhance the solar-to-thermal conversion efficiency. This study prepared a novel Ti₃C₂T_x/HCS-KH560-M2070 solvent-free nanofluid using a covalent grafting strategy, which was applied to a solar thermal system, effectively addressing the dispersion stability issue of nanoparticles in the fluid. The material features MXene nanosheets loaded with hollow carbon spheres (HCS) as the photothermal core, functionalized with an organic layer of KH560 and M2070 to confer remarkable nanoparticle stability. Dispersion of the solvent-free nanofluid in water yielded an aqueous nanofluid with exceptional light absorption, which achieved a photothermal conversion efficiency of 66.9% ± 1.5% at a mere 3.57 wt%. This high performance makes it a promising candidate for use in anti-icing systems and seawater desalination.