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Nano molybdenum disulfide possesses unique chemical and physical properties. In this paper molybdenum disulfide nanoparticles with spherical and flower-like structure are prepared via a hydrothermal method. Sodium molybdate and thioacetamide are taken as precursors, polyethylene glycol (PEG-20000), hexadecyl trimethyl ammonium chloride (CTAC) and anhydrous ethanol are used as additives. The properties of the product are characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that under acidic conditions, molybdenum disulfide nanoparticles with spherical shape are obtained when PEG-20000 and CTAC are added. The nanoparticles are uniform in size with a diameter of about 100 nm. Molybdenum disulfide nanoparticles with a flower-like structure are obtained when anhydrous ethanol is added. Their diameters under sulfuric acid and hydrochloric acid conditions are 190 nm and 70 nm, respectively. Yield analysis reveals that the highest yield (which can be up to 79 %) occurs by adding polyethylene glycol in a sulfuric acid environment.

Solid–gas thermochemical sorption heat storage is an efficient heat storage technology. Due to its high theoretical heat storage density, magnesium sulfate (MgSO4) is considered as one of the most potential sorption heat storage materials. Using zeolite 13X as the matrix, zeolite 13X/MgSO4 composite adsorbents were prepared, and the sorption–desorption performance was studied to reveal the potential heat storage capacity of the composite adsorbents. The addition of zeolite 13X aimed to enhance the hydration reaction rate by increasing the reaction surface area. The heat storage capacity of zeolite 13X/MgSO4 composite adsorbents with the salt mass fraction increasing from 5% to 20% was experimentally studied. Results showed that the composite sorbent with 20% MgSO4 offers the best heat storage performance. Under conditions of 25 °C and 60% RH, the mass sorption capacity of the composite sorbent containing 20% MgSO4 was 0.21 g g−1, and a heat storage density of 438.4 kJ kg−1 was achieved. With the mass fraction of MgSO4 being reduced from 20% to 5%, the sorption capacity and heat storage density of the composite decreased to 0.187 g g−1 and 378.8 kJ kg−1, respectively. To further enhance mass transfer, an appropriate amount of LiCl was added into the composite sorbent with 20% MgSO4, verifying that LiCl can not only improve the adsorption rate, but also increase the sorption capacity by 8.6%. [ABSTRACT FROM AUTHOR]

In this study, an expanded graphite (EG) with nano-CuS (EG/CuS) support material with a special morphology was prepared, with EG/CuS filled with different ratios of palmitic acid (PA). Finally, a PA/EG/CuS composite phase change thermal storage material with photothermal conversion performance was synthesized. The superb chemical and thermal stability of PA/EG/CuS was demonstrated by characterization and analysis of the experiments. EG, a multi-layer structured material, provides rich binding sites for PA and nano-CuS and constructs rich thermal conductivity paths, which effectively improves the thermal conductivity of PA/EG/CuS. It is noted that the maximum thermal conductivity of PA/EG/CuS reached 0.372 W m−1 K−1 and the maximum phase change thermal storage capacity reached 260.4 kJ kg−1, which proved the excellent thermal storage properties of PA/EG/CuS. In addition, PA/EG/CuS exhibits excellent photothermal conversion performance, and the experimental results demonstrated that the best photothermal conversion efficiency of PA/EG/CuS reached 81.4%. The PA/EG/CuS developed in this study provides a promising method for fabricating excellent conductive and low leakage composite phase change materials for solar energy utilization and energy storage. [ABSTRACT FROM AUTHOR]