Facing the complex variable high-temperature environment, electromagnetic wave (EMW) absorbing materials maintaining high stability and satisfying absorbing properties is essential. This study focused on the synthesis and EMW absorbing performance evaluation of TiN/Fe 2 N/C composite materials, which were prepared using electrostatic spinning followed by a high-temperature nitridation process. The TiN/Fe 2 N/C fibers constructed a well-developed conductive network that generates considerable conduction loss. The heterogeneous interfaces between different components generated a significant level of interfacial polarization. Thanks to the synergistic effect of stable dielectric loss and optimized impedance matching, the TiN/Fe 2 N/C composite materials demonstrated excellent and stable absorption performance across a wide temperature range (293–453 K). Moreover, TiN/Fe 2 N/C-15 achieved a minimum reflection loss (RL) of −48.01 dB and an effective absorption bandwidth (EAB) of 3.64 GHz at 2.1 mm and 373 K. This work provides new insights into the development of high-efficiency and stabile EMW absorbing materials under complex variable high-temperature conditions.
Thermochemical conversion is one of the most effective ways to upcycle organic solid wastes into fuels and/or value-added chemicals. In this study, the tandem hydropyrolysis/hydrocracking of polystyrene (PS) to produce ethylbenzene was studied using metal nitrides as catalysts. Fe, N co-doped carbon-based catalyst (Fe 2 N @ C) with core-shell structure was synthesized. The experimental results showed that carbon doping significantly improved the catalytic performance of iron nitride. The yield of ethylbenzene obtained from Fe 2 N @ C catalysis was 81 wt%, which is much higher than that of Fe 2 N (63.3 wt%) and commercial iron nitride (FeN, 4.9 wt%) under the hydropyrolysis temperature of 480 ℃, hydrocracking temperature of 280 ℃, and low H 2 pressure of 0.2 MPa. The high catalytic activity of Fe 2 N @ C is ascribed to the synergy of metal-based selective hydrogenation and acid site-mediated C-C bond activation. This work provides a flexible and efficient catalytic technology for the high-value utilization of polystyrene waste.
Rongrong Mu,Xiaowen Tang,Xinyan Huang,Yajie Ma,Huiming Lin
Fe 2 N@C nanospheres integrate NO release, PTT, and CDT for DFU therapy. • NIR-II-triggered hyperpyrexia amplifies POD-like activity of Fe 2 N@C. • Inorganic Fe 2 N@C acts as a novel NO donor with high release capacity. • Acidic biofilm microenvironment facilitates NO release and CDT activity. • Dynamic therapy possesses great potential on infective DFU therapy. Diabetic foot ulcer (DFU) is one of the most severe complications of diabetes, and its multiple pathological factors render treatment more challenging. We synthesized Fe 2 N@C nanomaterials to integrate synergistic photothermal therapy/chemical dynamic therapy/nitric oxide (PTT/CDT/NO) for DFU therapy. First, Fe 2 O 3 and urea were used as precursors to synthesize Fe 2 N@C nanomaterials via nitridation. The nanomaterial can serve as a new NO donor that releases NO triggered by H + and reactive oxygen species (H 2 O 2 and O 2 ). Furthermore, Fe 2 N@C possess superhigh peroxidase (POD)-like activity (V max = 21.1 Ms. −1 , pH 5.5), catalyzing endogenous H 2 O 2 into hydroxyl radicals ( OH). POD activity can also amplify NO and peroxynitrite (ONOO − ) production. In addition, Fe₂N@C nanomaterials reveal high near-infrared II (NIR-II) light harvest and photothermal conversion efficiency (43.94%). Hyperthermia also synergistically boosts POD-like activity and NO release. Under NIR-II laser irradiation, the combination of PTT/CDT and high NO concentration of can quickly clear bacterial infection. In addition, NO can down-regulate the expression of heat shock proteins (HSPs) to amplify PTT performance. Then, the mild NO supply (without irradiation) further facilitates the reversal of inflammation (M2 macrophage polarization) and tissue regeneration (angiogenesis). This dynamic synergistic therapy promotes fast normal DFU healing. Download: Download high-res image (259KB) Download: Download full-size image
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