Jianxin Chen

The ceramization of polymeric precursors via thermal treatment represents a simple, fast and highly efficient method for producing polymer-derived ceramics (PDCs). PDCs integrating two-dimensional (2D) materials attracted special interest because they combine the diverse functionalities of 2D materials (electrical conductivity and catalytic performance) with the excellent intrinsic properties of PDCs, such as high-temperature stability, oxidation and corrosion resistance. This review focuses on recent development of the composites integrating PDC and 2D materials (PDC–2D composites). The methods used to prepare those materials and the relationship between as-prepared structures and property or functionality are discussed in detail. Then, the applications of PDC–2D composites in electromagnetic wave absorption and shielding, energy storage, hydrogen evolution, and electrothermal devices are also addressed.

Microwave absorbents with specific morphology and structure have fundamental significance for tuning microwave absorption (MA). Herein, N-doped carbon sphere nanoparticles and hollow capsules were successfully fabricated via oxidative polymerization of dopamine in different mixed solutions, without any template preparation or etching process. Compared to solid particles, the microwave absorbents consisting of N-doped carbon with a hollow structure showed enormously enhanced MA performance, exhibiting a broad effective absorption bandwidth (from 12.7 GHz to 17.9 GHz) and a minimum reflection loss of −27.2 dB with a sample thickness of 2.0 mm. This work paves an attractive way for simple and eco-friendly preparation of advanced light weight microwave absorbents.

Demand for high‐performance electromagnetic (EM) wave absorbing materials with high‐temperature resistance is always urgent for application in a harsh environment. In this contribution, two‐dimensional material, Ti ₃ C ₂ T _x MXene, was introduced into a hyperbranched polyborosilazane. After pyrolyzation, the as‐prepared TiC/SiBCN ceramics present excellent EM wave absorption in X‐band. The TiC nanograins appearing after annealing provide multilevel reflection and interface polarization. Dipole polarization formed at interface defects, in company with interfacial polarization, also makes a great contribution to enhanced EM wave absorption. The TiC/SiBCN nanocomplex prepared with 5 wt% Ti ₃ C ₂ T _x MXene possesses a minimum reflection coefficient of −45.44 dB at 10.93 GHz and abroad bandwidth 8.4 and 12.4 GHz, almost covering the entire X‐band. Tuning the thickness in the range of 2.35‐2.54 mm, the effective absorption band can achieve the entire X‐band. And the EM wave absorbing performance has been maintained to a large extent at 600°C with the minimum reflection coefficient of −26.12 dB at 12.13 GHz and the effective absorption bandwidth of 2 GHz. Last but not the least, TiC/SiBCN ceramics offer a good thermal stability in argon as well as in air atmosphere, making it possible to serve in high‐temperature detrimental environments. This study is expected to provide a new perspective for the design of high‐performance absorbing materials that are able to be used in harsh environments, especially in high temperatures.

Fe–Ni alloy nanowires are widely used in high-density magnetic memories and catalysts due to their unique magnetic and electrochemical properties. Understanding the deformation mechanism and mechanical property of Fe–Ni alloy nanowires is of great importance for the development of devices. However, the detailed deformation mechanism of the alloy nanowires at different temperatures is unclear. Herein, the deformation mechanism of Fe–Ni alloy nanowires and their mechanical properties were investigated via the molecular dynamics simulation method. It was found that the local atomic pressure fluctuation of the Fe–Ni alloy nanowire surface became more prominent with an increase in the Ni content. At low temperature conditions (<50 K), the plastic deformation mechanism of the Fe–Ni alloy nanowires switched from the twinning mechanism to the dislocation slip mechanism with the increase in the Ni content from 0.5 at% to 8.0 at%. In the temperature range of 50–800 K, the dislocation slip mechanism dominated the deformation. Simulation results indicated that there was a significant linear relationship between the Ni content, temperature, and ultimate stress in the temperature range of 50–800 K. Our research revealed the association between the deformation mechanism and temperature in Fe–Ni alloy nanowires, which may facilitate new alloy nanowire designs.

We demonstrated an unconventional polymerization route to synthesize hydrophilic fluorescent organic nanoparticles (FONs) for multicolor cellular bioimaging in this contribution. The route benefits from our unexpected discovery of a rapid polymerization reaction between 1,6‐hexanediol dipropiolate and 2,4,6‐triazide‐1,3,5‐triazine under the catalysis of N,N,N′,N′′,N′′‐pentamethyldiethylenetriamine (PMDETA). Interestingly, the 2,4,6‐triazide‐1,3,5‐triazine and PMDETA system can also induce rapid free radical polymerization at room temperature. The as‐prepared FONs exhibited promising water solubility and stability with an average diameter of 20 nm. The excitation wavelength‐dependent fluorescent properties endow the FONs with blue, yellow, and red fluorescent emission under UV, blue, and green excitation, respectively. The cytotoxicity of FONs was investigated by using a Cell Counting Kit (CCK‐8) assay, which indicated good biocompatiblity. More importantly, the cell uptake experiment verified the FONs were excellent fluorescent nanoprobes for multicolor cellular bioimaging. Therefore, this unconventional route provides a novel fabrication strategy of highly hydrophilic FONs for biomedical applications.