Crystalline TiO2 shell microcapsules modified by Co3O4/GO nanocomposites for thermal energy storage and photocatalysis

Modified microcapsule is devised to achieve the integration of thermal energy storage and light energy conversion of solar energy. This composite structure integrates the nanomaterial composed of graphene oxide (GO) and Co 3 O 4 nanoparticles , on the microencapsulated paraffin coated by crystalline TiO 2 shell. Compared with TiO 2 @paraffin microcapsules, introducing a thermal conductivity improved element of Co 3 O 4 /GO substantially increased the thermal conductivity by 57.7% and retained specific heat capacity of 2.154 J·g −1 ·K −1 and latent heat above 140 J·g −1 . Microcapsules exhibited full-spectrum sunlight absorption ability, and the photothermal conversion efficiency was increased by 88.9%. Microcapsules are connected to the oxygen-containing functional groups on the flat of Co 3 O 4 /GO via hydrogen bonds and shared electron pairs, constituting a highly efficient Z-scheme heterojunction . By synergistic catalysis of photothermal, synergetic effects of semiconductor, and plasma resonance, the degradation rate of MB increased by 70.75%. This sophisticated multilevel structure of microcapsule possessed outstanding thermal cycling stability, which retains high thermal conductivity and specific heat capacity for microcapsule, while the latent heat loss rate was only 1.26%. This research implies a new insight for the field of energy storage microcapsules modification and multifunctional utilization of solar energy.