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Carbon-based magnetic composites with enhanced electromagnetic (EM) wave absorption ability have received intensive attention. Herein, a composite of N-graphene and small size magnetic Co nanoparticles (NPs) with advantages of excellent dielectric ability was synthesized through an in situ grown method. Under optimized conditions, Co NPs decorated on NGN (Co/NGN-2) have the best EM wave absorption performance, of which a minimum reflection loss of − 45.8 dB can be achieved at 13.48 GHz with a thin coating of 2 mm at 15 wt% filler loading in paraffin wax. The effective absorption bandwidth is about 4.6 GHz in Ku-band (12.4–18 GHz). Importantly, the effective absorption bandwidth can be extended by changing the thickness of the absorber. In fact, the coupling of NGN with Co NPs can form an effective impedance match, and thus the small size Co NPs with low density and good performance decorated on NGN material make the present method promising for EM applications. [ABSTRACT FROM AUTHOR]

In this work, a novel nano-sized mixed-crystal TiO2 catalyst was obtained under microwave irradiation in hydrogen peroxide solution and its sonocatalytic activity was also investigated through degradation of congo red dye. It was found that the sonocatalytic degradation effect of congo red using nano-sized mixed-crystal TiO2 powder was much higher than that using pure nano-sized rutile phase TiO2 powder. At last, the congo red dyes in aqueous solution were degraded completely and became some simple inorganic ions such as NO, SO and so on. The experiments indicated that the degradation method using such treated nano-sized rutile TiO2 powder as sonocatalyst could be used to treat those non- or low-transparent wastewaters effectively. [ABSTRACT FROM AUTHOR]