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.

A NiRu@N–C hybrid is fabricated and tested as an efficient catalyst for the hydrogen evolution reaction in a wide pH range.

Electrochemical nitrogen reduction to ammonia is proposed as a promising alternative to the Haber-Bosch process because it can be driven by renewable electricity at ambient conditions. Currently, the development of such a process is hampered by the lack of efficient electrocatalysts for the nitrogen reduction reaction (NRR). Herein, we report a super-rapid approach for the synthesis of flower-like Au microstructures (Au flowers) within 5 s. The obtained Au structures are assembled by staggered nanoplates as building blocks, which provide abundant electrocatalytically active sites for the NRR. The Au flowers achieve a high performance (NH yield: 25.57 μg h mg ; faradaic efficiency: 6.05 %), 100 % selectivity (no N H production), and long-term durability toward the electrochemical ammonia production. The work is highly valuable for the rapid synthesis of active catalysts for the NRR.

A carbon-bridge effect was adopted to explain the electromagnetic wave absorbing property related to the cross-linked framework structure of RGO–SCI composites.