In situ monitoring and characterizing kinetics of catalytic reaction with SERS on multifunctional Fe₃O₄/C/Au NPs in the magnetic field.

In this study, flower-like MoS₂ nanomaterials were synthesized by hydrothermal method with excess thiourea. The adsorption performance of MoS₂ adsorbent for methylene blue (MB) in azo dye wastewater was studied. The morphology, crystal phase, and microstructure of nano MoS₂ samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy. The effects of adsorption isotherm, kinetics, different hydrothermal time, and pH on the adsorption experiment were studied. The results showed that the MoS₂ adsorbent with a hydrothermal time of 1 h had good adsorption properties for MB. The adsorption data accord with the Langmuir isotherm model, and the maximum adsorption capacity of MoS₂ adsorbent is 200 mg/g, and the adsorption kinetics agrees well with the pseudo two-level model. The removal rate of MB is not significantly affected by the pH values. The large pH range can still maintain the removal rate above 93.47%, and the regeneration and recovery properties of MoS₂ were also explored. Finally, the adsorption mechanism of MoS₂ on MB is discussed.

Among many types of batteries, Li-ion and Li-S batteries have been of great interest because of their high energy density, low self-discharge, and non-memory effect, among other aspects. Emerging applications require batteries with higher performance factors, such as capacity and cycling life, which have motivated many research efforts on constructing high-performance anode and cathode materials. Herein, recent research about cathode materials are particularly focused on. Low electron and ion conductivities and poor electrode stability remain great challenges. Three-dimensional (3D) porous nanostructures commonly exhibit unique properties, such as good Li⁺ ion diffusion, short electron transfer pathway, robust mechanical strength, and sufficient space for volume change accommodation during charge/discharge, which make them promising for high-performance cathodes in batteries. A comprehensive summary about some cutting-edge investigations of Li-ion and Li-S battery cathodes is presented. As demonstrative examples, LiCoO₂, LiMn₂O₄, LiFePO₄, V₂O₅, and LiNi_1−x−yCo_xMn_yO₂ in pristine and modified forms with a 3D porous structure for Li-ion batteries are introduced, with a particular focus on their preparation methods. Additionally, S loaded on 3D scaffolds for Li-S batteries is discussed. In addition, the main challenges and potential directions for next generation cathodes have been indicated, which would be beneficial to researchers and engineers developing high-performance electrodes for advanced secondary batteries.

Gas environment detection has become more urgent and significant, for both industrial manufacturing and environment monitoring. Gas sensors based on a catalytically-sensing mechanism are one of the most important types of devices for gas detection, and have been of great interest during the past decades. However, even though many efforts have contributed to this area, some great challenges still remain, such as the development of sensitively and selectively sensing catalysts. In this review, two representative catalysis-based gas sensors, cataluminescent and conductometric sensors, the basis of optical and electric signal acquisition, respectively, are summarized comprehensively. The current challenges have been presented. Recent research progress on the working mechanism, sensing nanomaterials, and applications reported by our group and some other researchers have been discussed systematically. The future trends and prospects of the catalysis-based gas sensors have also been presented.

A novel two-dimensional nanocomposite Pt/Ti₃C₂T_x-CNT was synthesized for the non-invasive rapid detection of toluene, a lung cancer biomarker, via cataluminescence (CTL). Pt/Ti₃C₂T_x-CNT exhibited a good catalytic performance toward toluene. The CTL sensor based on Pt/Ti₃C₂T_x-CNT has the advantage of rapid response: The average response time was about 1 s, and the average recovery time was about 30 s. Moreover, the material has a wide scope of detection for toluene, and the limit of detection defined as 3 S/N was about 2 ppm. The optimal working temperature (150 °C) is lower than common sensors, so it has a broad prospect in the actual detection process. Aside from its weak response to formaldehyde, the sensor only exerted a strong response signal to toluene, and no response was observed to other VOCs, indicating that this CTL sensor has good selectivity for toluene. The possible sensing mechanism of CTL showed that toluene was oxidized to generate excited-state CO₂*, which emitted a luminescent signal when it returned to the ground state.