We report for the first time the preparation of highly stable graphene (GE)-based nanofluids with ionic liquid as base fluids (ionic liquid-based nanofluids (Ionanofluids)) without any surfactant and the subsequent investigations on their thermal conductivity, specific heat, and viscosity. The microstructure of the GE and MWCNTs are observed by transmission electron microscope. Thermal conductivity (TC), specific heat, and viscosity of these Ionanofluids were measured for different weight fractions and at varying temperatures, demonstrating that the Ionanofluids exhibit considerably higher TC and lower viscosity than that of their base fluids without significant specific heat decrease. An enhancement in TC by about 15.5% and 18.6% has been achieved at 25 °C and 65 °C respectively for the GE-based nanofluid at mass fraction of as low as 0.06%, which is larger than that of the MWCNT-dispersed nanofluid at the same loading. When the temperature rises, the TC and specific heat of the Ionanofluid increase clearly, while the viscosity decreases sharply. Moreover, the viscosity of the prepared Ionanofluids is lower than that of the base fluid. All these advantages of this new kind of Ionanofluid make it an ideal fluid for heat transfer and thermal storage.

The excellent photocatalytic activity of Ag ₃ PO ₄ /Ag/SiC can be ascribed to the efficient separation of photogenerated electron–hole pairs through the Z-scheme.

In this study, self-assembled and graphene oxide (GO) modified microcapsules of paraffin@mixed cellulose were prepared. The microstructure and morphology of the as-prepared phase-change composites were characterized by a polarizing microscope, SEM, FT-IR, XRD, and Raman spectrum. The results indicated that the paraffin@ethylcellulose (EC)/methylcellulose (MC)/GO composite consists of spherical particles that have core@shell structure, which indicates the absence of chemical reactions between the core (i.e., paraffin) and shell (i.e., EC/MC/GO) materials. The melting temperature (i.e., 49.7 °C) and latent heat (i.e., 152.2 J g⁻¹) of the paraffin@EC/MC/GO composite were determined through DSC. The encapsulation rate of paraffin in the composite can be as high as 85.4% based on the results of the DSC measurement. The as-prepared paraffin@EC/MC/GO composites had no leakage, which was observed by SEM, and possess perfect phase-change capability after experiencing 100 melting–freezing cycles. Furthermore, the microencapsulation was dispersed into the base fluid (i.e., water) to form a stable suspension, which shows enhanced photo-thermal conversion performance with temperature range from 30 to 80 °C. The efficiency of paraffin@EC/MC/GO-based phase-change slurry is maintained at 80% in a wide temperature range compared with that of paraffin@EC/MC-based phase-change slurry. The paraffin@EC/MC/GO composite with high thermal storage capacity, good thermal reliability and enhanced photothermal performance exhibits a good potential for using as a solar thermal storage material in practical applications.