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Photocatalysts comprising nanosized TiO2particles on activated carbon (AC) were prepared by a sol-gel method. The TiO2/AC composites were characterized by X-ray diffraction (XRD), thermogravimetric (TG) analysis, nitrogen adsorption, scanning electron microscope (SEM), transmission electron microscope (TEM), and energy dispersive X-ray (EDX). Their photocatalytic activities were studied through the degradation of Rhodamine B (RhB) in photocatalytic reactor at room temperature under ultraviolet (UV) light irradiation and the effect of loading cycles of TiO2on the structural properties and photocatalytic activity of TiO2/AC composites was also investigated. The results indicate that the anatase TiO2particles with a crystal size of 10–20 nm can be deposited homogeneously on the AC surface under calcination at 500°C. The loading cycle plays an important role in controlling the loading amount of TiO2and morphological structure and photocatalytic activity of TiO2/AC composites. The porosity parameters of these composite photocatalysts such as specific surface area and total pore volume decrease whereas the loading amount of TiO2increases. The TiO2/AC composite synthesized at 2 loading cycles exhibits a high photocatalytic activity in terms of the loading amount of TiO2and as high as 93.2% removal rate for RhB from the 400 mL solution at initial concentration of 2 × 10−5 mol/L under UV light irradiation.

Unique high-capacity MnO2/porous graphitic carbon (MnO2/PGC) composites were fabricated by a mild and efficient in situ precipitation approach using PGC derived from coal tar pitch as the carbonaceous precursor and KMnO4 as the manganese source. MnO2/PGC composites with reasonable surface areas (190–229 m2 g–1) retain the superior structure of interconnected nanopores and graphitic crystallite from PGC and contain evenly distributed MnO2 modified on the surface of the carbon skeleton in PGC, which can not only provide sufficient active sites for lithium-ion storage but also enhance electron transport capability and efficient lithium-ion diffusion capability. As a result of the synergistic effect of PGC and MnO2, MnO2/PGC composites as anode materials in lithium-ion batteries (LIBs) exhibit excellent reversible capacity, rate performance, and cycling stability. In particular, the MnO2/PGC-36 composite possesses a high initial reversible capacity of 1516 mAh g–1 at a current density of 0.05 A g–1 and an average reversible capacity of 399 mAh g–1 at a high rate of 5.00 A g–1. Moreover, such a MnO2/PGC-36 composite also exhibits a superior long-term cycling stability, with over 90.0% capacity retention after 400 cycles. These outstanding electrochemical performances demonstrate that the MnO2/PGC composite can be a promising anode material in LIBs for further practical application.

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