Highly Efficient Ir-CoOx Hybrid Nanostructures for the Selective Hydrogenation of Furfural to Furfuryl Alcohol.

Decoration of noble metals with transition-metal oxides has been intensively studied for heterogeneous catalysis. However, controllable syntheses of metal-metal oxide heterostructures are difficult, and elucidation of such interfaces is still challenging. In this work, supported IrCo alloy nanoparticles are transformed into supported Ir-CoOx close-contact nanostructures by in situ calcination and following selective reduction. Relative to Ir/Al2O3, Ir-CoOx/Al2O3 shows greatly enhanced activities for the hydrogenation of furfural derivatives to the corresponding furfuryl alcohol derivatives with more than 99% selectivity and demonstrates significantly improved activities and selectivity for hydrogenations of α,ß-unsaturated aldehydes to α,ß-unsaturated alcohols. The modification of Ir surfaces with CoOx prevents Ir nanoparticles from growing, achieving high thermal and catalytic stabilities. Theoretic calculation suggests that the better catalytic performance of Ir-CoOx/Al2O3 is ascribed to the Ir-CoOx interaction, which promotes the absorption of furfural as well as desorption of furfuryl alcohol, resulting in enhanced catalytic activities.

All-yarn triboelectric nanogenerator and supercapacitor based self-charging power cloth for wearable applications.

Despite rapid developments, multifunctional wearable electronics are still not significant in practical applications as compared to portable and stretchable power devices. In this paper, we present the flexible and easy large-scale production of single-electrode mode triboelectric nanogenerator (TENG) and supercapacitor yarn-based self-charging power fabric, for simultaneously converting and storing biomechanical energy. Fabricated using traditional knitting technologies, the self-charging power fabric can adapt to complex mechanical deformations owing to its high flexibility and stretchability. Additionally, the output characteristics of the TENG fabric were systematically investigated with the purpose of energy generation. The TENG fabric can generate a maximum peak power density of ∼90 mW·m-2using nylon as the contact material, with an operating frequency of 4 Hz. The as-prepared yarn-based supercapacitor exhibited high capacitance, good cycling stability, and flexibility, making it an appropriate wearable energy-storage device. Moreover, the proposed design uses energy harvested from biomechanical motions to sustainably power portable electronic devices. The results of this study indicate that the proposed design is a promising sustainable power source for wearable electronic devices.

Controlled Synthesis and Enhanced Catalytic Activity of Well-Defined Close-Contact Pd-ZnO Nanostructures.

In this study, PdZn-ordered intermetallic nanoparticles (NPs) were prepared in liquid phase by butyllithium co-reduction of their precursors at 240 °C. Through calcination and subsequent reduction with H2, the synthesized PdZn NPs were then in situ transformed into Pd-ZnO heteroaggregate nanocatalysts on alumina supports. Various characterization techniques, such as diffuse reflectance Fourier transform infrared with CO probes, transmission electron microscopy, X-ray diffraction, H2 temperature-programmed reduction, and X-ray photoelectron spectra, reveal that PdZn NPs are ordered intermetallic compounds, and in situ transformation of PdZn alloy NPs results in close-contact Pd-ZnO heteroaggregates, where the interfaces are highly active and the interaction between Pd and ZnO prevents the active particles from agglomeration. The catalytic hydrogenations of nitrophenols over Pd/Al2O3 and Pd-ZnO/Al2O3 were investigated. The results show that Pd-ZnO/Al2O3 illustrates an enhanced catalytic activity relative to Pd/Al2O3, and no obvious activity degradation was observed in the recycle catalytic experiments over such nanostructures. It is concluded that the Pd-ZnO interaction not only enhances the catalytic hydrogenation activity but also promotes the thermal and catalytic stability.

Role of Ammonium Derivative Ligands on Optical Properties of CH3NH3PbBr3 Perovskite Nanocrystals.

Amines, ammonium salts, and their combination with organic acids are commonly employed ligands during the synthesis of colloidal perovskite nanocrystals (PNCs). However, the role of surface coordination, derived from different ammonium derivative ligands, on the optical properties of PNCs remains poorly understood. In this study, octylamine (OA), octylammonium bromide (OABr), and oleic acid (OAc) were applied, standing for amine, ammonium salt, and organic acid, respectively. The effects of four different types of ligands, including OA, OABr, OA-OAc, and OABr-OAc, on the surface coordination and subsequently optical properties of CH3NH3PbBr3 PNCs were comparatively investigated. Compared to amine ligand, the ammonium salt could coordinate to both surface cations and anions of PNCs to passivate their surface defects more effectively, leading to enhanced optical properties including higher photoluminescence (PL) spectral intensities and PL quantum yield. Moreover, the combination of OAc with amine rather than ammonium salt ligand could trigger the protonation-deprotonation reaction to further improve their coordination effect on a PNC's surface, thus leading to significantly enhanced optical properties of PNCs. This study clarified the surface coordination of different ammonium derivative ligands and their role on the optical properties of PNCs, which could guide the design of ligands during the synthesis of PNCs.

Improved LC/MS Methods for the Analysis of Metal-Sensitive Analytes Using Medronic Acid as a Mobile Phase Additive.

Phosphorylated compounds and organic acids with multiple carboxylate groups are commonly observed to have poor peak shapes and signal in LC/MS experiments. The poor peak shape is caused by the presence of trace metals, particularly iron, contributed from a variety of sources within the chromatographic system. To ameliorate this problem, different solvent additives were investigated to reduce the amount of metal in the flow path to achieve better analytical performance for these metal-sensitive compounds. Here, we introduce the use of a solvent additive that can significantly improve the peak shapes and signal of metal-sensitive metabolites for LC/MS analysis. Moreover, the additive is shown to be amenable for other metal-sensitive applications, such as the analysis of phosphopeptides and polar phosphorylated pesticides, where the instruments could be used in either positive or negative analysis mode.

Fabrication of TiO2 Nanostructures on Ti3SiC2 Substrate by Anodic Oxidation.

A TiO2 nanostructure was prepared on a Ti3SiC2 substrate with different water and NH4F concentrations in a fluoride-containing ethylene glycol electrolyte via an anodization process using the same constant-anodization potentials, anodization duration and temperature. The as-prepared samples were characterized by a field-emission scanning electron microscope equipped with an energy dispersive X-ray spectroscope, as well as by X-ray diffraction and X-ray photoelectron spectroscopy. The influence of the anodizing parameters and annealing temperature on the morphology of the nanostructure and the phase structure was studied. The results showed that the scattered TiO2 nanotubes and TiO2 nanoporous films were successfully fabricated in the glycol electrolyte containing (3.0 wt%) NH4F +(5.0 vol%) H2O. The as-prepared samples before calcination were amorphous and could transform to the anatase phase at temperatures higher than 500 °C. As the annealing temperature increased, the crystallization of the anatase phase was enhanced, and the rutile phase appeared at 600 °C. The as-prepared samples mainly consisted of oxides. Ti2O3 and SiO2 oxides were present in addition to TiO2.

A Generic Method for Preparing Hollow Mesoporous Silica Catalytic Nanoreactors with Metal Oxide Nanoparticles inside Their Cavities.

We report a facile and generic method for the synthesis of hollow mesoporous silica nanoreactors (HMSNs) with small-sized metal oxide nanoparticles (NPs) inside their cavities. They were made by deposition of silica onto metal-containing charge-driven polymer micelles and subsequent calcination. The micelles consist of 1) negatively charged supramolecular polyelectrolyte chains of bis-ligand-bound metal ions, and 2) water-soluble, neutral/positive diblock copolymers. Owing to the facile coordination between transition-metal ion and the employed bidentate ligand, a series of HMSNs with <2 nm Mx Oy NPs inside cavities (M=Mn, Co, Ni, Cu, or Zn) were obtained by simply varying the metal ions inside the micelles. The developed method circumvents the pre- and post-synthesis of metal oxide NPs; after calcination, hollow mesoporous nanostructures containing small-sized metal oxide NPs inside their cavities are directly obtained. The Cox Oy -functionalized HMSNs catalyze the degradation of various dyes with H2 O2 .

NO oxidation catalysis on copper doped hexagonal phase LaCoO3: a combined experimental and theoretical study.

Cobalt-based perovskite catalysts showed excellent performance towards NO-NO2 oxidation. We systematically investigated the influence of different levels of Cu-doping on the catalytic performance of hexagonal phase LaCoO3 (LaCo1-xCuxO3 (x = 0.1, 0.2, 0.3)) for NO oxidation. The catalytic activities of the oxide catalysts followed the sequence: LaCo0.9Cu0.1O3 > LaCoO3 > LaCo0.8Cu0.2O3 > LaCo0.7Cu0.3O3 where the highest NO conversion for LaCo0.9Cu0.1O3 was 82% at 310 °C. The relevant structural characterizations were conducted by XRD, BET, FTIR and TEM. The interaction between Co and Cu promoted the conversion of NO to NO2. Upon increasing the Cu doping content, a decrease of the performance resulted from the generation of isolated CuO on the surface of the oxides, confirmed using H2-TPR and XPS. Combined with first-principle calculations, we explored the reaction mechanism of NO oxidation on the surface and found that Cu doping would facilitate the reaction by decreasing the energy of oxygen vacancy formation and the NO2 desorption barrier from Co- or Cu-nitrite.

Size effect and material property effect of the impactor on the damage modes of the single-layer Kiewitt-8 reticulated dome.

The dynamic response of large space structures under accidental impact has been the subject of intense research since the occurrence of the 9/11 incident. In the present paper, using the 3D ANSYS/LS-DYNA, size effect and material property effect of the impactor on the damage modes of the single-layer Kiewitt-8 reticulated dome were investigated, respectively, where the impactor was the cylinder and the impact direction was vertical. Firstly, analytical results with the rigid impactor indicated that the impactor size can change the damage mode of the reticulated dome. It was found that the probability happening to the global collapse has an obvious rise with the size increase of the impactor. Furthermore, the deformable impactor was considered to figure out the difference with the rigid impactor; the comparisons indicated that the deformable impactor, which has the same mass and the same striking velocity with the rigid impactor, can contribute to the occurrence of the global collapse at a certain initial striking condition.

Depression screening using hybrid neural network.

Depression is a common cause of increased suicides worldwide, and studies have shown that the number of patients suffering from major depressive disorder (MDD) increased several-fold during the COVID-19 pandemic, highlighting the importance of disease detection and depression management, while increasing the need for effective diagnostic tools. In recent years, machine learning and deep learning methods based on electroencephalography (EEG) have achieved significant results in the field of automatic depression detection. However, most current studies have focused on a small number of EEG signal channels, and experimental data require special processing by professionals. In this study, 128 channels of EEG signals were simply filtered and 24-fold leave-one-out cross-validation experiments were performed using 2DCNN-LSTM classifier, support vector machine, K-nearest neighbor and decision tree. The current results show that the proposed 2DCNN-LSTM model has an average classification accuracy of 95.1% with an AUC of 0.98 for depression detection of 6-second participant EEG signals, and the model is much better than 72.05%, 79.7% and 79.49% for support vector machine, K nearest neighbor and decision tree. In addition, we found that the model achieved a 100% probability of correctly classifying the EEG signals of 300-second participants.

The Influence of Alumina Bubbles on the Properties of Lightweight Corundum-Spinel Refractory.

The use of a lightweight corundum-spinel refractory in working lining could reduce the thermal conductivity of industrial furnaces. In this study, bubble alumina was introduced to realize a lightweight Al2O3-MgAl2O4 refractory assisted by the reactive sintering of Al2O3 and MgO. The effects of alumina bubble content and sintering temperature on the phase compositions, microstructure and properties of the lightweight refractory were investigated. The results indicated that the overall performance of the lightweight Al2O3-MgAl2O4 refractory was mainly dominated by the content of alumina bubbles. The bulk density, compressive strength and thermal conductivity all decreased when the alumina bubble content increased from 10 to 30 wt%. Meanwhile, the sintering temperature also significantly affected the properties of the obtained refractory. It is worth noting that specimens fired at 1650 °C achieved a high refractoriness under load (RUL) of more than 1700 °C when alumina bubble content was less than 30 wt%, which was comparable to that of the dense Al2O3-MgAl2O4 refractory. The thermal conductivity of the obtained samples was remarkably decreased to no more than 2.13 W/(m·K). In order to overcome the trade-off between the light weight of the refractory and overall performance, it is feasible to adjust the content of alumina bubbles and raise the sintering temperature appropriately.

Improving Anti-Coking Properties of Ni/Al2O3 Catalysts via Synergistic Effect of Metallic Nickel and Nickel Phosphides in Dry Methane Reforming.

A series of NiP-x/Al2O3 catalysts containing different ratio of metallic nickel to nickel phosphides, prepared by varying Ni/P molar ratio of 4, 3, 2 through a co-impregnation method, were employed to investigate the synergistic effect of metallic nickel-nickel phosphides in dry methane reforming reaction. The Ni/Al2O3 catalyst indicates good activity along with severe carbon deposition. The presence of phosphorus increases nickel dispersion as well as the interaction between nickel and alumina support, which results in smaller nickel particles. The co-existence of metallic nickel and nickel phosphides species is confirmed at all the P contained catalysts. Due to the relative stronger CO2 dissociation ability, the NiP-x/Al2O3 catalysts indicate obvious higher resistance of carbon deposition. Furthermore, because of good balance between CH4 dissociation and CO2 dissociation, NiP-2/Al2O3 catalyst exhibits best resistance of carbon deposition, few carbon depositions were formed after 50 h of dry methane reforming.

Correction: The fabrication of hollow ZrO2 nanoreactors encapsulating Au-Fe2O3 dumbbell nanoparticles for CO oxidation.

Correction for 'The fabrication of hollow ZrO2 nanoreactors encapsulating Au-Fe2O3 dumbbell nanoparticles for CO oxidation' by Fan Yang et al., Nanoscale, 2021, 13, 6856-6862, DOI: 10.1039/D1NR00173F.

Improving the steric hindrance effect of linear sulfonated acetone-formaldehyde dispersant and its performance in coal-water slurry.

Dispersants can have a substantial impact on the rheological characteristics of coal-water slurry (CWS). Due to their advantages in cost and synthesis, linear dispersants are currently most often employed in the commercial manufacturing of CWS. However, this kind of dispersant gives limited performance because of its weak adsorption and steric hindrance effect on the coal-water interface. This work describes a new linear dispersant (PSAF) with a significant steric hindrance effect that was created by incorporating phenolic groups into its molecular architecture, which gives higher maximum coal content (63.79 wt%) than that (63.11 wt%) from sulfonated acetone-formaldehyde (SAF). The synthesis mechanism was investigated using GPC, FT-IR and NMR. Various technologies were used to explore the rheological characteristics and dispersion mechanism for CWS prepared with PSAF. PSAF as well as SAF showed monolayer adsorption on the surface of coal and displayed a higher adsorption layer thickness (3.5 nm). PSAF dispersant presents stand-up adsorption rather than lie-down adsorption of SAF because of its strong π-π action, resulting in a stronger steric hindrance effect and improved rheological performance. This work can provide guidelines for the development of a high-performance dispersant as well as an understanding of the dispersal process for CWS.

Improved liquid chromatography-MS/MS of heparan sulfate oligosaccharides via chip-based pulsed makeup flow.

Microfluidic chip-based hydrophilic interaction chromatography (HILIC) is a useful separation system for liquid chromatography-mass spectrometry (LC-MS) in compositional profiling of heparan sulfate (HS) oligosaccharides; however, ions observed using HILIC LC-MS are low in charge. Tandem MS of HS oligosaccharide ions with low charge results in undesirable losses of SO(3) from precursor ions during collision induced dissociation. One solution is to add metal cations to stabilize sulfate groups. Another is to add a nonvolatile, polar compound such as sulfolane, a molecule known to supercharge proteins, to produce a similar effect for oligosaccharides. We demonstrate use of a novel pulsed makeup flow (MUF) HPLC-chip. The chip enables controlled application of additives during specified chromatographic time windows and thus minimizes the extent to which nonvolatile additives build up in the ion source. The pulsed MUF system was applied to LC-MS/MS of HS oligosaccharides. Metal cations and sulfolane were tested as additives. The most promising results were obtained for sulfolane, for which supercharging of the oligosaccharide ions increased their signal strengths relative to controls. Tandem MS of these supercharged precursor ions showed decreased abundances of product ions from sulfate losses yet more abundant product ions from backbone cleavages.

Hollow and mesoporous aluminosilica-encapsulated Pt-CoOx for the selective hydrogenation of substituted nitroaromatics.

Hollow and mesoporous aluminosilica nanoreactors (HMANs) with Pt-CoOx cores (∼4.7 nm) and hollow aluminosilica shells (∼50 nm) were designed by a selective etching method. The Pt-CoOx@HMANs demonstrate a greatly enhanced activity and selectivity for the hydrogenation of various substituted nitroaromatics compared to Pt@HMANs and Pt-CoOx@SiO2.

The fabrication of hollow ZrO2 nanoreactors encapsulating Au-Fe2O3 dumbbell nanoparticles for CO oxidation.

Nanosized Au catalysts suffer from serious sintering problems during synthesis or catalytic reactions at high temperatures. In this work, we integrate dumbbell-shaped Au-Fe3O4 heterostructures into hollow ZrO2 nanocages to make Au-Fe2O3@ZrO2 yolk-shell nanoreactors with high activity as well as ultra-high sintering resistance for high-temperature CO oxidation. The synthesis starts with the fabrication of a (Au-Fe3O4)@SiO2@ZrO2 core-shell nanostructure with a Au-Fe3O4 dumbbell nanoparticle (DB) core and SiO2/ZrO2 double shells, followed by calcination and the selective removal of the inner SiO2 shell with alkaline solution to obtain Au-Fe2O3@ZrO2 nanoreactors. The retained ZrO2 hollow (outer) shells protect the Au NPs from aggregation at temperatures up to 900 °C and show excellent long-term stability. Compared to Au@ZrO2 yolk-shell nanoreactors, Au-Fe2O3@ZrO2 shows improved activity in CO oxidation due to the active Au-Fe2O3 interface. This strategy can be extended to other yolk-shell nanoreactors with various nanocomposites and for different catalytic reactions.

High-throughput profiling of the serum N-glycome on capillary electrophoresis microfluidics systems: toward clinical implementation of GlycoHepatoTest.

We developed a 3 h procedure for preparing serum N-glycans and labeling them with 8-aminopyrene-1,3,6-trisulfonic acid (APTS) by sequential addition of reagents to the serum and incubation in a polymerase chain reaction (PCR) thermocycler. Moreover, we succeeded in analyzing these samples by capillary electrophoresis on three commercial microfluidics-based platforms: the MCE-202 MultiNA, the 2100 Bioanalyzer, and a modified prototype of the eGene system which were originally designed for nucleic acid separation and detection. Although these instruments use short separation channels, our technical improvements made it possible to reliably measure the N-glycans constituting GlycoHepatoTest. This test comprises a panel of biomarkers that allows follow-up of liver fibrosis patients starting from the early stage. In this way and for the first time, we demonstrate a clinical glycomics assay on an affordable, robust platform so that clinical chemistry laboratories can exploit glycomics in the diagnosis and monitoring of chronic liver disease. Another potential application is the rapid screening of the N-glycosylation of recombinant glycoproteins produced for pharmaceutical use.

Improved hydrophilic interaction chromatography LC/MS of heparinoids using a chip with postcolumn makeup flow.

Heparan sulfate (HS) and heparin are linear, heterogeneous carbohydrates of the glycosaminoglycan (GAG) family that are modified by N-acetylation, N-sulfation, O-sulfation, and uronic acid epimerization. HS interacts with growth factors in the extracellular matrix, thereby modulating signaling pathways that govern cell growth, development, differentiation, proliferation, and adhesion. High-performance liquid chromatography (HPLC)-chip-based hydrophilic interaction liquid chromatography/mass spectrometry has emerged as a method for analyzing the domain structure of GAGs. However, analysis of highly sulfated GAG structures decasaccharide or larger in size has been limited by spray instability in the negative-ion mode. This report demonstrates that addition of postcolumn makeup flow to the amide-HPLC-chip configuration permits robust and reproducible analysis of extended GAG domains (up to degree of polymerization 18) from HS and heparin. This platform provides quantitative information regarding the oligosaccharide profile, degree of sulfation, and nonreducing chain termini. It is expected that this technology will enable quantitative, comparative glycomics profiling of extended GAG oligosaccharide domains of functional interest.

Surface alumina species on modified titanium dioxide: A solid-state (27)Al MAS and 3QMAS NMR investigation of catalyst supports.

(27)Al MAS and 3QMAS NMR have been used to study Al(2)O(3)/TiO(2) catalyst supports synthesized via excess-solution impregnation and surface sol-gel methods. Temperature and alumina loading level strongly affect chemical states of aluminum oxide species observed. Surface cations, Al(H2O)6(3+), a surface alumina monolayer, and disordered transitional aluminas (multilayers) and alpha-alumina, coexist on the TiO(2) surface. Chemical shift and quadrupole coupling constants are reported for the major species identified in 3QMAS experiments. Gold particle catalysts prepared from supports calcined at 500 degrees C have optimum catalytic activity in CO oxidation, and smallest gold particle size for supports, which show maximum monolayer type octahedral alumina on the titania surface.