Search

Molybdenum carbide is one of non‐precious metal materials and it is a promising electrocatalyst for hydrogen production. Synthesis and improvement of molybdenum carbide's catalytic performance is of great significance. Herein, carbon‐based Mo2C with hybrid phase of MoO2 was fabricated by matching the composition of Mo and C derived from pomelo peel and optimizing raw carbon amount and prolysis temperature. The resulting MoO2/Mo2C@C is composed of loose microspheres with mesoporous microstructure and is self‐assembled from nanoparticles. The results show that MoO2/Mo2C@C2 material exhibits excellent HER performance and only a low overpotentials of 143 mV is needed to drive the current density of 10 mA cm−2 in alkaline solution, and Tafel slopes are only 63.4 mV dec−1, respectively. Notably, it has potential application at low overpotentials to drive large current density and this strategy also provides a universal route to prepare non‐noble metal catalyst with hybrid phase of oxide/carbide. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) materials possess special physical and chemical properties. They have been proved to have potential application advantage in the microwave absorption (MA) and electromagnetic interference (EMI) shielding. Particularly, they exhibit positive shielding and absorbing response to EMI. Here, the research progress of preparation, electromagnetic performance and microwave shielding/absorbing mechanisms of 2D composite materials are introduced. Effective preparation routes including introducing heteroatoms, constructing unique structures and 2D composite materials are described. Furthermore, the application prospects and challenges for the development of novel EMI materials are expatiated. [ABSTRACT FROM AUTHOR]

Molybdenum carbide possessing a Pt‐like d‐band electronic structure is considered as one of potential candidates of electrocatalysts and it shows intrinsic catalytic property. However, a high carbonizing temperature easily leads to the coalescence of nanoparticles (NPs). Here, we propose a simple sol‐gel route to achieve high dispersity of carbide NPs by designing a Mo‐involved xerogel. The results show that molybdenum carbide NPs are dispersed and anchored on the nitrogen‐doped carbon nanosheets (Mo2C@NC). Ultrathin carbon layers resemble graphene and the network structures act as a support of carbide NPs, which can hinder NPs' coalescence effectively. Nanpoparticles cross‐coupled on network‐structure nanosheets display the grid shapes. Electrochemical studies indicate that Mo2C@NC material exhibits outstanding hydrogen evolution performance in alkaline electrolyte. [ABSTRACT FROM AUTHOR]