Highly efficient solar photothermal conversion of graphene-coated conjugated microporous polymers hollow spheres

Highly efficient harvesting, transfer, and storage of solar energy are of great significance for the sustainability of society Herein, we report the design and synthesis of conjugated microporous polymers hollow spheres (CMPs-HS) coated by graphene (GCMPs-HS) and compounded with the phase change material (PCM) octadecanol (GCMPs@ODA) for efficient solar photothermal conversion. The as-synthesized CMPs-HS shows a high specific surface (519.95 m² g^-1 and 309.26 m² g^-1), good thermostability, and lower thermal conductivity (0.33 W m^-2h^-1). By coating graphene, the light absorption remained about 90% in the visible light range, which allows light harvest for photothermal conversion. Taking the GCMPs-HS as a functional layer for the solar steam generation (SSG) system, a high evaporation efficiency of near 90% is obtained. After inhaling octadecanol, GCMPs@ODA are prepared and their latent heats are measured to about 217.4 J g^-1 and 224.6 J g^-1. Under 1 sun irradiation, the photothermal conversion efficiencies of GCMPs@ODA are measured to be 87.15% and 85.83%, the above merits applied in different conditions are superior to photothermal conversion materials reported in the literature. Thus, among the above merits, the fabricated materials are the competitive candidate which shows the great potential in the efficient application of solar energy.