Piezoelectric Property Enhancement of PZT Thick Film via Pulsed Flash Poling during Sintering

Lead zirconate titanate (PZT) is a widely used piezoelectric material due to its high piezoelectric response. High-temperature thermal sintering and poling are two important steps to obtain a high piezoelectric property PZT film by densifying the film and reorienting the dipoles along the desired direction, respectively. However, these two steps are processed separately, which increases the duration and complexity of the process. Moreover, a high-temperature process limits the selection of electrode and substrate material to those materials with very high melting points. This paper experimentally demonstrates the feasibility of  sintering and poling simultaneously, providing a novel approach to prepare PZT film. Moreover, this paper investigates the effect of cyclic temperature excursions above and below the Curie temperature on the piezoelectric properties of PZT thick film. Photonic sintering with high-intensity, short-duration pulsed flashes was used to fuse and merge PZT particles. Simultaneously, an electrical poling field (20 kV/cm) was applied through the PZT film to reorient the PZT dipoles. The entire processing duration was less than 5 min. The resultant piezoelectric property of the PZT film was analyzed, yielding high g33 (22.6 × 10–3 Vm/N), d33 (626 × 10–12 m/V), and permittivity (3130) values, indicating good sensing and actuating capabilities. This enhanced piezoelectric performance is superior to the groups of PZT films prepared using traditional processes. This approach has potential applications for obtaining high-performance piezoelectric devices, such as piezoelectric energy harvesters, memory storage devices, or bulk acoustic wave resonators

Trimetallic FeCoNi@C Nanocomposite Hollow Spheres Derived from Metal–Organic Frameworks with Superior Electromagnetic Wave Absorption Ability

Organic ligands and metal ions in the metal–organic frameworks (MOFs, a type of porous magnetic metal/carbon nanocomposites obtained through high-temperature carbonization) have caused widespread concerns in the field of microwave absorption because of the existence of various microwave loss mechanisms in these materials. However, MOF-driven microwave absorbing materials with high absorption intensity and wide absorption band still require further research and development. In this work, hollow sphere trimetallic FeCoNi@C microwave absorbing materials via high-temperature carbonization were obtained using FeCoNi-based MOF-74 (FeCoNi-MOF) as the precursor. The effects of different carbonization conditions on the microwave absorption properties of the materials were studied. FeCoNi-MOF-74 annealed at 700 °C showed superior microwave absorption capacity, where the RL value reached −64.75 dB at 15.44 GHz corresponding to the actual application thickness of the absorber (only 2.1 mm), and the minimum RL values reached −69.03 dB at 5.52 GHz. Furthermore, the as-prepared sample can fully cover the Ku band and X band at only 2.1 and 3.1 mm, respectively. The maximum EAB reached 8.08 GHz (9.92–18 GHz) when the thickness of the absorber was 2.47 mm. Such remarkable absorption performance is attributed to the synergetic effects between the multiple loss mechanisms of the FeCoNi@C, and the improved impedance matching characteristic came from the hollow sphere morphology

From Natural Attapulgite to Mesoporous Materials: Methodology, Characterization and Structural Evolution

In this paper, we report the synthesis of hexagonally ordered aluminum-containing mesoporous silica, Al-MCM-41, from natural attapulgite (Al-substituted Si8O20Mg5(OH)2(H2O)4·4H2O) without addition of silica or aluminum reagents. A pretreatment process involving sequential mechanical grinding and acid leaching is critical to the successful use of attapulgite as a source of both Si and Al in the surfactant-templated hydrothermal synthesis of Al-MCM-41. The resulting mesophase had a surface area of 1030 m2/g and an average pore diameter of 3.7 nm with narrow pore size distribution. The influence of changes in processing parameters, such as grinding time, hydrothermal conditions, and calcination temperature, on the textural characteristics of the Al-MCM-41 products is studied. Investigations of the mechanism of structural evolution indicate that grinding of attapulgite results in amorphization and partial structural breakdown, transformation of the fibrous mineral bundles into rod-shaped particles, and partial displacement of octahedrally coordinated Al3+ ions into the Si−O tetrahedral framework. Subsequent acid etching dissolves the Mg-rich octahedral sheets to produce samples with variable texture due to modifications in the residual aluminum-containing silicate sheets and associated silica fragments. Solid-state magic-angle spinining NMR spectroscopy indicates that Al3+ ions are located in both octahedral and tetrahedral sites in the as-synthesized Al-MCM-41 samples, but that the calcined products consist primarily of Al3+ ions substituted in the tetrahedrally coordinated silica matrix of the ordered channel wall structure

Highly Active Ni–Ru Bimetallic Catalyst Integrated with MFI Zeolite-Loaded Cerium Zirconium Oxide for Dry Reforming of Methane

The dry reforming of methane (DRM) is a new potential technology that converts two major greenhouse gases into useful chemical feedstocks. The main challenge faced by this process is maintaining the catalyst with high catalytic activity and long-term stability. Here, a simple and effective preparation route for the synthesis of functional nanomolecular sieve catalysts (NiRuxCZZ5) from kaolinite tailings was developed for dry reforming of methane with CO2. The silica monoliths with flower-like spherical and micropore structures (ZSM-5) were prepared by crystal growth method, and the metal components were loaded by ultrasonic-assisted impregnation method. The NiRu0.5CZZ5 catalyst exhibited excellent catalytic performance (maxmium CO2 and CH4 conversions up to 100 and 95.6%, respectively) and very good stability (up to 100h). The interfacial confinement and the strong support interaction are principally responsible for the excellent catalytic activity of the catalyst. The in situ DRIFTS was used to elucidate the possible carbon conversion steps, and stable surface intermediates were also identified

Additional file 2 of Establishment and evaluation of an overlap extension polymerase chain reaction technique for rapid and efficient detection of drug-resistance in Mycobacterium tuberculosis

Additional file 2. The amino acid sequence associated with the rpo-BembB-katG-inhA fusion fragment

Additional file 1 of Establishment and evaluation of an overlap extension polymerase chain reaction technique for rapid and efficient detection of drug-resistance in Mycobacterium tuberculosis

Additional file 1. The DNA sequence of the rpoB-embB-katG-inhA fusion fragment

High Stability of the Ni–YCe/Diatomite Catalyst for CO₂ Methanation: The Synergistic Coupling of Citric Acid and Y₂O₃

Carbon dioxide (CO2) methanation exhibits great potential for achieving high-value utilization of CO2 to fulfill the goal of carbon neutrality. Here, a novel nickel–yttrium–cerium/diatomite (Ni–YCe/Dia) composite was constructed by the in situ growth of thin membrane-like Ni–YCe oxides on the Dia template. Distinct from conventional Ni-based catalysts, Dia improved the dispersion of Ni–YCe oxide nanoparticles and provided extra hydroxyl groups for CO2 adsorption; citric acid remarkably enhanced the dispersion of Ni species, thus creating favorable conditions for the rapid dissociation of H2; most importantly, introducing Y species improved the dispersion of Ni nanoparticles and the anti-carbon deposition capacity of the catalysts. Such characteristics endow Ni–YCe/Dia composites with exceptional catalytic activity for CO2 methanation, with more than 85% CO2 conversion and 99% CH4 selectivity in a stability test up to 150 h, which is better than most reported Ni-based catalysts. In situ DRIFTS analysis revealed that the −OH groups on the surface of Dia exhibited a remarkable ability to activate CO2. This study provides a new perspective on the rational regulating of structural assemblage between metal oxides and natural minerals for high-performance CO2 methanation

Additional file 1: of Synthesis and Characterization of Modified BiOCl and Their Application in Adsorption of Low-Concentration Dyes from Aqueous Solution

Figure S1. Adsorption capacities of BiOCl and Fe/BiOCl toward MB (a) and AO (b). Figure S2. Adsorption capacities of MO, MB, RhB, and AO as a function of time in mixed dye solutions on BiOCl. Figure S3. Adsorption capacities of MO, MB, RhB, and AO as a function of time in mixed dye solutions on Fe/BiOCl. Figure S4. Freundlich isotherm for adsorption RhB on BiOCl (a) and Fe/BiOCl (b). Figure S5. Pseudo-second-order kinetics for adsorption RhB on BiOCl (a) and Fe/BiOCl (b). Table S1. Parameters based on the pseudo-second-order kinetics for adsorption RhB on BiOCl and Fe/BiOCl. Figure S6. FT-IR spectra (a) and photographs of various samples (1-RhB, 2-BiOCl, 3-Fe/BiOCl, 4-BiOCl after adsorption, 5-Fe/BiOCl after adsorption, 6-BiOCl after adsorption and photodegradation, 7-Fe/BiOCl after adsorption and photodegradation). (DOCX 669 kb

Precious-Metal Nanoparticles Anchored onto Functionalized Halloysite Nanotubes

Natural halloysite nanotubes (HNTs) were functionalized with a silane coupling agent with the aim of tuning the loading rate and dispersion of precious-metal nanoparticles. The samples were characterized by FTIR spectroscopy, TEM, and XPS. The results indicated that a large number of precious-metal nanoparticles were anchored on the surface of the silanized HNTs, with an average diameter of ∼3 nm. The functionalized HNTs contain a large number of functional groups (−NH2 or −SH groups) that have one lone electron pair and can form a chemical bond complex with nanoparticles. Because of bond formation between the nanoparticles and the functional groups, most of the nanoparticles (NPs) are anchored by the functional groups, resulting in the formation of nanoparticle–functional group complexes. Bond formation between the nanoparticles and the functional groups was demonstrated, and furthermore, atomic-level interfaces for NPs anchored onto functionalized HNTs were depicted. The chemical immobilization of precious-metal nanoparticles onto silanized HNTs could avoid particle aggregation and movement, thus leading to a higher catalytic efficiency

Biomimetic Tremelliform Ultrathin MnO₂/CuO Nanosheets on Kaolinite Driving Superior Catalytic Oxidation: An Example of CO

Highly efficient three-dimensional (3D) kaolinite/MnO2–CuO (KM@CuO–NO3) catalysts were synthesized by a mild biomimetic strategy. Kaolinite flakes were uniformly wrapped by ultrathin tremelliform MnO2 nanosheets with thicknesses of around 1.0–1.5 nm. Si–O and Al–O groups in kaolinite hosted MnO2 nanosheets to generate a robust composite structure. The ultrathin MnO2 lamellar structure exhibited excellent stability even after calcination above 350 °C. Kaolinite/MnO2 exhibited abundant edges, sharp corners, and interconnected diffusion channels, which are superior to the common stacked structure. Open channels guaranteed fast transportation and migration of CO and O2 during CO oxidation. The synthesized KM@CuO–NO3 achieved a 90% CO conversion efficiency at a relatively low temperature (110 °C). Furthermore, the abundant oxygen vacancies on KM@CuO-NO3 assisted the adsorption and activation of oxygen species and thus enhanced the oxygen mobility and reactivity in the catalytic process. The mechanism results suggest that CuO introduced to the catalyst not only acted as CO active sites but also weakened the Mn–O bond, subsequently improved the mobilities of the oxygen species, which was found to contribute to its high activity for CO oxidation. This study provides new conceptual insights into rationally regulating structural assembly between transition metal oxides and natural minerals for high-performance catalysis reactions