Synthesis of hybrid dual-MOF encapsulated phase-changing material for improved broadband light absorption and photothermal conversion enabling efficient solar energy storage

To improve the overall solar-thermal energy harvesting efficiency of encapsulated phase change materials (EPCM), a novel hierarchic SiO2/PCN-224/PB (ES-PCN-PB) composite shell was developed and synthesized through in-situ growth of PCN-224 decorated with PB particles onto SiO2 encapsulated PCM. The corresponding topologies, chemical characteristics, crystallinity, optical properties, and thermal induction capacity of the ES-PCN-PB capsules were thoroughly evaluated. The articulated strategy attained phase-change enthalpies of about 124.15 J/g, with a differential temperature of 28.88 ± 0.22 °C achieving a magnified photothermal energy conversion efficiency of 96.20% due to the broadband solar spectrum absorbance and effective light to heat conversion through the electron-hole generation and non-radiative relaxation. The combination of PCN-224 and PB decorated shell was realized to be a practical approach to improve structural stability, durability, and light-harvesting ability. The coupling of the two MOFs insinuates broad spectral absorption and photothermal conversion improvement which augments a considerable contribution to straightforward solar energy harvesting in numerous PCM applications such as temperature management of greenhouses, solar water heating systems, solar cookers, and solar-thermal electricity generating systems.