Graphene is highly desirable as an electromagnetic wave absorber because of its high dielectric loss and low density. Nevertheless, pure graphene is found to be non-magnetic and contributes to microwave energy absorption mostly because of its dielectric loss, and the electromagnetic parameters of pure graphene, which are out of balance, result in a bad impedance matching characteristic. In this paper, we report a facile solvothermal route to synthesize laminated magnetic graphene. The results show that there have been significant changes in the electromagnetic properties of magnetic graphene when compared with pure graphene. Especially the dielectric Cole-Cole semicircle suggests that there are Debye relaxation processes in the laminated magnetic graphene, which prove beneficial to enhance the dielectric loss. We also proposed an electromagnetic complementary theory to explain how laminated magnetic graphene, with the combined advantages of graphene and magnetic particles, helps to improve the standard of impedance matching for electromagnetic wave absorbing materials. Besides, microwave absorption properties indicate that the reflection loss of the as-prepared composite is below À10 dB (90% absorption) at 10.4-13.2 GHz with a coating layer thickness of 2.0 mm. This further confirms that the nanoscale surface modification of magnetic particles on graphene makes graphenebased composites have a certain research value in electromagnetic wave absorption.

The OHC shows superior performance as an anode material for LIBs with a high reversible capacity (1181 mA h g−1 at 0.1 A g−1) and an excellent rate capability (304 mA h g−1 at 5 A g−1).

Recent research into graphene-based materials is largely focused on graphene quantum dots (GQDs) and their optical properties. A facile method has been developed to extract GQDs from reduced graphene oxide (RGO) by the ozonation pre-oxide method. The as-prepared GQDs, which were 2-5 nm in diameter, exhibited strong fluorescence activity ranging from $355 nm to $440 nm. The prepared GQDs possessed strong fluorescence with quantum yields from 3.18% to 9.48%. What's more, the fluorescence properties of the GQDs could be determined by tuning the pH of the ozonation system. We speculated the mechanisms of ozonation, thermal and hydrothermal treatment. We found that pyrocatechol could lead to fluorescence quenching of the GQDs, which might produce novel potential for the detection of targets.

A microwave (MW)-assisted synthesis method for preparation of fluorescent BSA-stabilized and HSAprotected gold nanoclusters (BSA-AuNCs and HSA-AuNCs) has been developed. The reaction time can be shortened from tens of hours to several minutes, thanks to the superheating and non-thermal effects of the MW energy. The optimal experimental conditions including concentrations of BSA, HAuCl 4 and NaOH and the MW programme are investigated in detail. The as-synthesised BSA-AuNC product is well characterized by UV-vis spectroscopy, fluorescence spectroscopy, HRTEM, XPS, and IR spectroscopy. The HSA-AuNCs display strong red emission which is efficiently quenched by nitrogen oxides (NO x ), demonstrating its great potential in determining the intracellular concentration of NO x . The proposed MW-assisted synthesis method is simple, fast and should be applicable to prepare various protein-or enzyme-protected metal nanoclusters.