Novel NiMoO4-integrated electrode materials were successfully prepared by solvothermal method using Na2MoO4·2H2O and NiSO4·6H2O as main raw materials, water, and ethanol as solvents. The morphology, phase, and structure of the as-prepared materials were characterized by SEM, XRD, Raman, and FT-IR. The electrochemical properties of the materials in supercapacitors were investigated by cyclic voltammetry, constant current charge–discharge, and electrochemical impedance spectroscopy techniques. The effects of volume ratio of water to ethanol (W/E) in solvent on the properties of the product were studied. The results show that the pure phase monoclinic crystal NiMoO4 product can be obtained when the W/E is 2:1. The diameter and length are 0.1–0.3 µm and approximately 3 µm, respectively. As an active material for supercapacitor, the NiMoO4 nanorods material delivered a discharge specific capacitance of 672, 498, and 396 F/g at a current density of 4, 7, and 10 A/g, respectively. The discharge specific capacitance slightly decreased from 815 to 588 F/g with a retention of 72% after 1000 cycles at a current density of 1 A/g. With these superior capacitance properties, the novel NiMoO4 integrated electrode materials could be considered as promising material for supercapacitors.

Two phases of nickel sulfide (α-NiS and β-NiS) nanoarchitectures were successfully and controllably synthesized by a facile solvothermal method with two different solvents of alcohol and water, respectively. The products were characterized by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, and UV-vis diffuse reflectance spectrophotometer. The sphere-like shape for α-NiS and cross-like shape composed of nanorods for β-NiS are uniform and well distributed as well as their size. Both α-NiS and β-NiS powders were used as counter electrodes (CEs) in dye-sensitized solar cells (DSSCs). It is found that the DSSC with an α-NiS CE performs much better than the one with a β-NiS CE. The energy conversion efficiency of the former was 5.2%, whereas the latter was 4.2%, about 20% increment.

Mixed solvent of ethanol and water using FeSO4⋅7H2O and (NH2)2CS as precursors with polyvinylpyrrolidone as surfactant was used to synthesize cubic FeS2 (pyrite) crystals. Crystalline phase and surface morphologies of the crystals were characterized by X-ray diffraction and scanning electron microscopy, respectively. Volume ratio of solvent, reaction temperature, reaction time, and sulfur source were found to be the key parameters for the formation of pure pyrite crystals. Optimal micron-size pyrite crystals were successfully grown from a mixed solvent of ethanol and water with a volume ratio of 3:2, heated to a reaction temperature of 180 °C, and maintained for 36 h with thiourea as the sulfur source.