Hierarchical WS2-WO3 Nanohybrids with Flower-like p-n Heterostructures for Trimethylamine Detection.

The detection of trimethylamine (TMA) is critically important due to its toxic and flammable nature, which poses significant risks to human health and the environment. However, achieving high response, rapid kinetics, selectivity, and low operating temperatures in TMA sensing remains challenging. In this study, WS2/WO3 nanohybrids with flower-like hierarchical structures were synthesized via an in situ sulfurization process, utilizing varying amounts of thioacetamide to control the sulfurization state of WO3. These novel hierarchical WS2/WO3 nanohybrids exhibit remarkable selectivity towards TMA, as well as rapid response and recovery characteristics. Specially, the optimal WS2/WO3 sensor, composed of 5% WS2/WO3 nanohybrids, demonstrates exceptional TMA sensing performance, including a high response (19.45 at 10 ppm), good repeatability, reliable long-term stability, and a low theoretical detection limit (15.96 ppb). The superior sensing capabilities of the WS2/WO3 nanohybrids are attributed to the formation of p-n heterojunctions at the interface, the unique hierarchical structures, and the catalytic activity of WS2. Overall, this work provides a straightforward and versatile approach for synthesizing multifunctional nanomaterials by combining metal oxide micro-flowers with transition metal dichalcogenide nanoflakes for applications in monitoring TMA in complex environments.

Layered double hydroxide-based electrode materials derived from metal-organic frameworks: synthesis and applications in supercapacitors.

Metal-organic frameworks (MOFs) have emerged as promising electrode materials for supercapacitors (SCs) due to their highly porous structures, tunable chemical compositions, and diverse morphologies. However, their applications are hindered by low conductivity and poor cycling performance. A novel approach for resolving this issue involves the growth of layered double hydroxides (LDHs) using MOFs as efficient templates or precursors for electrode material preparation. This method effectively enhances the stability, electrical conductivity, and mass transport ability of MOFs. The MOF-derived LDH exhibits a well-defined porous micro-/nano-structure, facilitating the dispersion of active sites and preventing the aggregation of LDHs. Firstly, this paper introduces synthesis strategies for converting MOFs into LDHs. Subsequently, recent research progress in MOF-derived LDHs encompassing pristine LDH powders, LDH composites, and LDH-based arrays, along with their applications in SCs, is overviewed. Finally, the challenges associated with MOF-derived LDH electrode materials and potential solutions are discussed.

In Situ Fabrication of SnS2/SnO2 Heterostructures for Boosting Formaldehyde-Sensing Properties at Room Temperature.

Formaldehyde, as a harmful gas produced by materials used for decorative purposes, has a serious impact on human health, and is also the focus and difficulty of indoor environmental polution prevention; hence, designing and developing gas sensors for the selective measurement of formaldehyde at room temperature is an urgent task. Herein, a series of SnS2/SnO2 composites with hollow spherical structures were prepared by a facile hydrothermal approach for the purpose of formaldehyde sensing at room temperature. These novel hierarchical structured SnS2/SnO2 composites-based gas sensors demonstrate remarkable selectivity towards formaldehyde within the concentration range of sub-ppm (0.1 ppm) to ppm (10 ppm) at room temperature. Notably, the SnS2/SnO2-2 sensor exhibits an exceptional formaldehyde-sensing performance, featuring an ultra-high response (1.93, 0.1 ppm and 17.51, 10 ppm), as well as good repeatability, long-term stability, and an outstanding theoretical detection limit. The superior sensing capabilities of the SnS2/SnO2 composites can be attributed to multiple factors, including enhanced formaldehyde adsorption, larger specific surface area and porosity of the hollow structure, as well as the synergistic interfacial incorporation of the SnS2/SnO2 heterojunction. Overall, the excellent gas sensing performance of SnS2/SnO2 hollow spheres has opened up a new way for their detection of trace formaldehyde at room temperature.

Direct synthesis of ethanol from dimethyl ether and syngas over combined H-Mordenite and Cu/ZnO catalysts.

Ethanol was directly synthesized from dimethyl ether (DME) and syngas with the combined H-Mordenite and Cu/ZnO catalysts that were separately loaded in a dual-catalyst bed reactor. Methyl acetate (MA) was formed by DME carbonylation over the H-Mordenite catalyst. Thereafter, ethanol and methanol were produced by MA hydrogenation over the Cu/ZnO catalyst. With the reactant gas containing 1.0% DME, the optimized temperature for the reaction was at 493 K to reach 100% conversion. In the products, the yield of methanol and ethanol could reach 46.3% and 42.2%, respectively, with a small amount of MA, ethyl acetate, and CO(2). This process is environmentally friendly as the main byproduct methanol can be recycled to DME by a dehydration reaction. In contrast, for the physically mixed catalysts, the low conversion of DME and high selectivity of methanol were observed.