Substrate-Free Fabrication of Single-Crystal Two-Dimensional Gold Nanoplates for Catalytic Application

Two-dimensional (2D) gold nanoplates (AuNPLs) have shown potential in catalysis, photonics, electronics, sensing, and biomedicine fields due to their high aspect ratio, fascinating surface chemistry, and quantum-size effect. Therefore, the synthesis of substrate-free, size-controlled single-crystal gold (Au) nanoplates is highly desirable for the development of catalysis and optical near-field enhancement applications. EDTA and hydroxide anions were used in this study to stimulate the formation of microscale single-crystal gold nanoplates under hydrothermal conditions. The reaction temperature, amount of EDTA, and hydroxyl anions all have a significant effect on the morphologies and size distributions of the gold nanoplates. The gold nanoplates had an average side length of between 3 and 11 μm. The application of the microscale single-crystal gold nanoplates as a nanocatalyst proved their excellent catalytic activity and recyclability for the catalysis of 4-nitrophenol to 4-aminophenol, implying that the large-size gold nanoplates were promising in heterogeneous catalysis applications

Additional file 1 of Ultra-High Response Detection of Alcohols Based on CdS/MoS2 Composite

Additional file 1. Details of materials required for additional experiments. Figure S1 The photograph of sensing test system and bench. Figure S2 XRD patterns of CdS/MoS2 composites. Figure S3 EDX point scan spectrum result

Enhanced H₂S Gas-Sensing Performance of Ni-Doped ZnO Nanowire Arrays

Ni-doped ZnO nanowire arrays (Ni–ZnO NRs) with different Ni concentrations are grown on etched fluorine-doped tin oxide electrodes by the hydrothermal method. The Ni–ZnO NRs with a nickel precursor concentration of 0–12 at. % are adjusted to improve the selectivity and response of the devices. The NRs’ morphology and microstructure are investigated by scanning electron microscopy and high-resolution transmission electron microscopy. The sensitive property of the Ni–ZnO NRs is measured. It is found that the Ni–ZnO NRs with an 8 at. % Ni precursor concentration have high selectivity for H2S and a large response of 68.9 at 250 °C compared to other gases including ethanol, acetone, toluene, and nitrogen dioxide. Their response/recovery time is 75/54 s. The sensing mechanism is discussed in terms of doping concentration, optimum operating temperature, gas type, and gas concentration. The enhanced performance is related to the regularity degree of the array and the doped Ni3+ and Ni2+ ions, which increases the active sites for oxygen and target gas adsorption on the surface

Recyclable Ag-Deposited TiO₂ SERS Substrate for Ultrasensitive Malachite Green Detection

An ultrasensitive Ag-deposited TiO2 flower-like nanomaterial (FLNM) surface-enhanced Raman scattering (SERS)-active substrate is synthesized via a hydrothermal method, and Ag nanoparticles (NPs) are deposited through electron beam evaporation. Malachite green (MG), which is widely used in aquaculture, is employed to assess the surface-enhanced Raman scattering (SERS) properties of TiO2/Ag FLNMs. They exhibit ultrasensitivity (limit of detection (LOD) of MG reaches 4.47 × 10–16 M) and high reproducibility (relative standard deviations (RSDs) are less than 13%); more importantly, the TiO2/Ag FLNMs are recyclable, as enabled by their self-cleaning function due to TiO2 photocatalytic degradation. Their recyclability is achieved after three cycles and their potential application is examined in the actual system. Finite difference time domain (FDTD) simulations and the charge-transfer (CT) mechanism further prove that the excellent SERS properties originate from localized surface plasmon resonance (LSPR) of Ag NPs and the coupling field between Ag and TiO2 FLNMs. Therefore, TiO2/Ag FLNMs show promising application in aquaculture

Boron-Based Polyphosphazene-Functionalized Mxene Nanosheets for Polypropylene Composites with Improved Mechanical Properties and Flame Retardancy Applications

Developing high-performance resins with exceptional thermal oxidation stability, flame retardancy, smoke release suppression, and mechanical properties is an important industrial challenge. However, current flame-retardant design strategies often compromise other composite material properties. Especially when using polyolefin, unsaturated polyester, and other noncharred materials, it is usually necessary to add large amounts of flame-retardant fillers. In this study, a nanosynergist (Ti3C2Tx@PPD) for functionalizing Ti3C2Tx nanosheets with boron-based polyphosphazene was designed and adopted for a piperazine pyrophosphate/polypropylene (PAPP/PP) system as an application example. By controlling the chemical environment of cyclotriphosphazene, the condensed phase characteristics of polyphosphazene were preserved, but also an atypical vapor phase flame-retardant mechanism was activated. The combination of P/N/B elements and Ti3C2Tx exhibited excellent catalytic char-forming performance compared to others in the literature. Only 2% of incorporated Ti3C2Tx@PPD reduced the total heat released from the composite by 66.3%, the total smoke released by 71.8%, and the fire growth index by 49.4%. The incorporation of Ti3C2Tx@PPD inhibited deterioration of the mechanical properties of the composite. In addition, the pyrolysis path of Ti3C2Tx was revealed under a special environment. This study lays the foundation for the functional design of Ti3C2Tx nanomaterials that can be used in various applications that require high-performance resins

Innovative Design and Preparation of Hierarchical BP–OH@HAP Structure: Study on Flame Retardancy and Mechanical Characteristics of UPR Nanocomposites

The flammability and brittleness of unsaturated polyester resin (UPR) were two serious problems that limited its application in high-precision fields. Here, the rod-shaped hydroxyapatite (HAP) was anchored on the surface of hydroxylated black phosphorus nanosheets (BP–OH) through a hydrothermal reaction to obtain a highly stable black phosphorus-based nano flame retardant (BP–OH@HAP). Owing to the exposure of many hydroxyl groups, BP–OH@HAP was well dispersed in the UPR matrix, and UPR nanocomposites with 0.5 wt % BP–OH@HAP realized a 71% increase in impact strength. The presence of BP–OH@HAP also greatly inhibited the combustion of UPR nanocomposites. In detail, the UPR composites with 2 wt % BP–OH@HAP achieved a 47.0% decrease in peak heat release rate (PHRR) along with 23.1% reductions in total heat release (THR), revealing the excellent ability of BP–OH@HAP to inhibit polymer combustion. In addition, UPR/BP–OH@HAP 2.0 achieved a 46 s increase in the time to PHRR (tPHRR) and a 62% reduction in the fire growth index (FGI), indicating that the fire spread of UPR/BP–OH@HAP 2.0 was significantly suppressed. Therefore, this work obtained the UPR/BP–OH@HAP nanocomposite with high fire safety through the innovation of inorganic nanotechnology, which provided new research ideas for improving the toughness and flame-retardant properties of UPR-based nanocomposites