Photo-thermal conversion properties of MXene/metal-organic-frameworks-based nanofluids for solar energy harvesting

This study focuses on enhancing solar energy capture efficiency by introducing innovative hybrid nanofluids for use in solar thermal collectors, whose performance largely depends on the absorption properties of the working fluid. The newly developed hybrid nanofluids, MXene/NH2-UiO66 (Zr) (noted as MX/UO66) and MXene/MIL-88B (Fe) (noted as MX/ML88), were synthesized using an in-situ solvothermal method, combining annealed Ti3C2Tx MXenes with water-stable metal-organic frameworks (MOFs). These nanofluids achieved high efficiency at low concentrations, providing both economic and performance benefits. Comprehensive testing compared the photothermal properties of these hybrids with single-component UO66 and ML88 nanofluids. The MX structures significantly expanded the absorption range and intensity for UO66 and ML88, with MXUO66 and MXML88 displaying superior thermal conductivity and light absorption compared to single-component fluids. At a concentration of 220 ppm, MXUO66 and MXML88 achieved photothermal efficiencies of 85 % and 79 %, respectively, improving by 24.5 % and 11.3 % over UO66 and ML88 alone. Results indicate that the MX-UO66 combination is particularly effective, demonstrating the strong potential of these composites for optimizing solar energy systems. This work highlights the capability of nanoporous materials with enhanced photothermal properties, underscoring their adaptability for various solar applications and the importance of optimizing collector designs to minimize heat losses.