A Novel Dye-Modified Metal-Organic Framework as a Bifunctional Fluorescent Probe for Visual Sensing for Styrene and Temperature.

A novel fluorescent probe (C460@Tb-MOFs) was designed and synthesized by encapsulating the fluorescent dye 7-diethylamino-4-methyl coumarin (C460) into a terbium-based metal-organic framework using a simple ultrasonic impregnation method. It is impressive that this dye-modified metal-organic framework can specifically detect styrene and temperature upon luminescence quenching. The sensing platform of this material exhibits great selectivity, fast response, and good cyclability toward styrene detection. It is worth mentioning that the sensing process undergoes a distinct color change from blue to colorless, providing conditions for the accurate visual detection of styrene liquid and gas. The significant fluorescence quenching mechanism of styrene toward C460@Tb-MOFs is explored in detail. Moreover, the dye-modified metal-organic framework can also achieve temperature sensing from 298 to 498 K with high relative sensitivity at 498 K. The preparation of functionalized MOF composites with fluorescent dyes provides an effective strategy for the construction of sensors for multifunctional applications.

Construction of novel noble-metal-free MoP/CdIn2S4 heterojunction photocatalysts: Effective carrier separation, accelerating dynamically H2 release and increased active sites for enhanced photocatalytic H2 evolution.

Developing novel photocatalysts with high performance is significant for the practical application of photocatalytic H2 production. Herein, novel and noble-metal-free heterojunction photocatalysts contained CdIn2S4 nanoparticles and bulk MoP were prepared. The H2-production rate of optimal MoP/CdIn2S4 (MPCIS) composites achieved at 286.10 µmol g-1h-1, which was nearly 2.2 times that of CdIn2S4-1 %Pt (130.51 µmol g-1h-1). Electrochemical and PL results displayed that MoP cocatalyst could vastly boost the carrier separation efficiency of CdIn2S4. The high carrier separation efficiency maybe put down to the Fermi level rearrangement between MoP and CdIn2S4. The linear sweep voltammograms tests showed that, compared to CdIn2S4, CdIn2S4 with 30 %MoP (30MPCIS) has smaller Tafel slopes and lower H2 evolution overpotentials, which contributed to facilitate H2 release in kinetics. The 30MPCIS composites possess higher Cdl value and MoP has Pt-like electronic structure, so that MoP could offer abundant surface reaction sites of MPCIS composites for HER. Aforementioned results demonstrate that MoP may have great potential in replacing precious metal Pt for photocatalytic H2 production. It is expected that this study can provide new insights into developing the novel sulfide-based heterojunction photocatalysts with MoP as cocatalyst for resultful photocatalytic H2 generation.

A novel noble-metal-free Mo2C-In2S3 heterojunction photocatalyst with efficient charge separation for enhanced photocatalytic H2 evolution under visible light.

Currently, designing novel noble-metal-free photocatalysts with efficient carriers migration and catalytically active sites have been a researching hotspot in photocatalytic hydrogen evolution. In this paper, a novel noble-metal-free Mo2C-In2S3 heterojunction was synthesized by a simple hydrothermal method. Morphology characterization revealed In2S3 was attached to Mo2C. Electrochemical results showed Mo2C improved the interface conductivity, and promoted the transportation of photogenerated carriers. Under visible light, the optimal Mo2C-In2S3 composite achieved a H2 generation rate of 535.58 µmol h-1 g-1, which was 175.6 and 25.8 times higher than pristine In2S3 (3.05 µmol h-1 g-1) and In2S3-1% Pt (20.73 µmol h-1 g-1). In addition, a reasonable mechanism of the elevated photocatalytic activity was also discussed. This study demonstrates commercial Mo2C has an important effect of separating carriers and replacing Pt as co-catalyst in heterojunctions. This research also provides a method to design and synthesize new noble-metal-free photocatalysts for excellent hydrogen production activity.

Double Z-scheme system of silver bromide@bismuth tungstate/tungsten trioxide ternary heterojunction with enhanced visible-light photocatalytic activity.

The ternary heterojunction of silver bromide@bismuth tungstate/tungsten trioxide (AgBr@Bi2WO6/WO3) was designed and synthesised by hydrothermal and deposition-precipitation approaches. The composites were characterised by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy (XPS). The photoabsorption range and bandgaps of the photocatalysts were analysed by ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS). Compared with Bi2WO6/WO3 or AgBr alone, the AgBr@Bi2WO6/WO3 composites displayed higher visible-light photocatalytic performance for degrading rhodamine B (RhB). AgBr@Bi2WO6/WO3 with 40% AgBr concentration was optimum for photocatalytic activity. Radical-trapping experiments revealed that superoxide anion radicals (O2-) and holes (h+) were the active species during photocatalytic degradation and that O2- was the dominant active species. Therefore, the increased photocatalytic activity of AgBr@Bi2WO6/WO3 was attributed to the atypical double Z-scheme system, which effectively improved the transfer and separation of electron-hole pairs in ternary heterojunction structures.