Solvent-Free Synthesis Enables Encapsulation of Subnanometric FeOx Clusters in Pure Siliceous Zeolites for Efficient Catalytic Oxidation Reactions.

Metal/metal oxide clusters possess a higher count of unsaturated coordination sites than nanoparticles, providing multiatomic sites that single atoms do not. Encapsulating metal/metal oxide clusters within zeolites is a promising approach for synthesizing and stabilizing these clusters. The unique feature endows the metal clusters with an exceptional catalytic performance in a broad range of catalytic reactions. However, the encapsulation of stable FeOx clusters in zeolite is still challenging, which limits the application of zeolite-encapsulated FeOx clusters in catalysis. Herein, we design a modified solvent-free method to encapsulate FeOx clusters in pure siliceous MFI zeolites (Fe@MFI). It is revealed that the 0.3-0.4 nm subnanometric FeOx clusters are stably encapsulated in the 5/6-membered rings intersectional voids of the pure siliceous MFI zeolites. The encapsulated Fe@MFI catalyst with a Fe loading of 1.4 wt % demonstrates remarkable catalytic activity and recycle stability in the direct oxidation of methane, while also promoting the direct oxidation of cyclohexane, surpassing the performance of conventional zeolite-supported Fe catalysts.

Enabling direct oxidation of ethane to acetaldehyde with oxygen using supported PdO nanoparticles.

Industrial-scale production of acetaldehyde relies heavily on homogeneous catalysts. Here, we used ethane as the feedstock and developed ZSM-5-supported PdO nanoparticles for the direct oxidation of ethane to acetaldehyde by utilizing O2 and CO. PdO nanoparticles clearly demonstrate effective activity and prevent the further deep oxidation of acetaldehyde.

Long-term immobilization of cadmium and lead with biochar in frozen-thawed soils of farmland in China.

The problem of potentially toxic elements (PTEs) in farmland is a key issue in global pollution prevention and control and has an important impact on environmental safety, human health, and sustainable agricultural development. Based on the climate background of high-latitude cold regions, this study simulated freeze-thaw cycles through indoor tests. Different initial conditions, such as biochar application rates (0%, 1%, 2%) and different initial soil moisture contents (15%, 20%, 25%), were set to explore the morphological changes in cadmium (Cd) and lead (Pb) in soil and the response relationship to the changes in soil physicochemical properties. The results indicate that soil pH decreases during freeze-thaw cycles, and soil alkalinity increases with increasing biochar content. Freeze-thaw cycles caused the total amount of PTEs to have a U-shaped distribution, and the amount of PTEs in the soluble (SOL) and reducible (RED) fraction increased by 0.28-56.19%. Biochar reduced the amount of Cd and Pb migration in the soil, and an increase in soil moisture content reduced the availability of Cd and Pb in the soil. Freezing and thawing damaged the soil structure, and biochar reduced the fractionation of small particle aggregates by enhancing the stability of soil aggregates, thereby reducing the soil's ability to adsorb Cd and Pb. In summary, for farmland soil remediation and pollution control, the application of biochar has a certain ability to optimize soil properties. Considering the distribution of PTEs in the soil and the physicochemical properties of the soil, the application of 1% biochar to soil with a 20% moisture content is optimal for regulating seasonally frozen soil remediation.

A Ladder-type Heteroheptacene 12H-Dithieno[2',3':4,5]thieno[3,2-b:2',3'-h]fluorene Based D-A Copolymer with Strong Intermolecular Interactions toward Efficient Polymer Solar Cells.

Ladder-type electron-donating units for D-A copolymers applied in polymer solar cells usually comprise multiple tetrahedral carbon bridges bonded with out-of-plane alkyl chains for desirable solubility for device processing. However, molecular packing of resultant copolymers in the solid state and charge transport within devices are also impeded in spite of with multiple fused aromatic backbones. To mitigate this issue, a structurally well-defined ladder-type electron-donating heteroheptacene, 12H-dithieno[2',3':4,5]thieno[3,2-b:2',3'-h]fluorene (DTTF) with an extended conjugated backbone and a single tetrahedral carbon bridge attached with two bulky alkyl chains was designed and synthesized. The copolymerization of DTTF with 4,7-bis(4-hexylthiophen-2-yl)benzo[c][1,2,5]thiadiazole (DTBT) afforded a soluble D-A copolymer (PDTTF-DTBT) with a medium optical band gap of 1.72 eV and low-lying HOMO level at -5.36 eV. PDTTF-DTBT unprecedentedly exhibits strong intermolecular stacking ability and presents preferential face-on orientation on both ZnO and PEDOT:PSS layers. The improved packing order and appropriate phase separation of both the copolymer and PC71BM in the bulk heterojunction blend on the ZnO layer over on the PEDOT:PSS layer lead to much improved power conversion efficiency of ∼8.2% in the inverted solar cell device, among the highest for reported ladder-type D-A copolymers. The research demonstrates that it is an effective method to incorporate a single tetrahedral carbon bridge to the molecular center of a ladder-type heteroacene with heavily extended π-conjugation to prepare D-A copolymers toward highly efficient PSCs.

Mechanical Properties and Microstructure of Class C Fly Ash-Based Geopolymer Paste and Mortar.

This paper presents workability, compressive strength and microstructure for geopolymer pastes and mortars made of class C fly ash at mass ratios of water-to-fly ash from 0.30 to 0.35. Fluidity was in the range of 145-173 mm for pastes and 131-136 mm for mortars. The highest strengths of paste and mortar were 58 MPa and 85 MPa when they were cured at 70 °C for 24 h. In XRD patterns, unreacted quartz and some reacted product were observed. SEM examination indicated that reacted product has formed and covered the unreacted particles in the paste and mortar that were consistent with their high strength.

[Determination of phenylethanolamine A residue in feeds by ultra performance liquid chromatography-tandem mass spectrometry].

A method was developed for the determination of the residue of phenylethanolamine A in feeds by ultra performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS/MS). The phenylethanolamine A in sample was extracted with phosphoric acid methanol solution. The extract was purified and concentrated by an MCX column. In the positive mode, an ultra-performance BEH C18 column (100 mm x 2.1 mm, 1.7 microm) was used to separate the phenylethanolamine A, and the separation was carried out on a Waters UPLC system by using gradient elution with acetonitrile and 0.1% (v/v) formic acid aqueous solution as the mobile phases at a flow rate of 0.4 mL/min. The qualitative and quantitative analysis was carried out by multi-reaction monitoring (MRM) mode, in which the analyte was ionized by electrospray ionization interface (ESI). The results showed that, the calibration curve was linear in the range of 0.5-100 microg/kg (r > 0.999), the limit of quantification (S/N > 10) was 10 microg/kg, the recoveries ranged from 79.6% to 86.2%, and the relative standard deviations (RSDs) were between 3.1% and 6.7%. The real sample tests showed that the method is convenient and reliable.

[Dishen Qufeng Decoction for treating allergic rhinitis: a randomized controlled trial].

OBJECTIVE: To observe the clinical therapeutic effects of Dishen Qufeng Decoction (DSQFD), a compound traditional Chinese herbal medicine, in treatment of allergic rhinitis. METHODS: Sixty cases of allergic rhinitis were selected and randomized into DSQFD group (30 cases) and cetirizine group (30 cases), and the patients were orally administered DSQFD and cetirizine respectively. The integrals of patients' symptoms, such as sneezing, nose running, nasal occlusion and nasal itching, signs in the nasal conchae and peripheral blood eosinophil (EOS) count were abserved count before and after treatment. RESULTS: DSQFD obviously improved the symptoms and signs of allergic rhinitis. The total response rate of DSQFD treatment was 83.3%, while that of the cetirizine treatment was 86.7%; the EOS counts in both groups were significantly decreased. These results showed statistical difference between the two groups. CONCLUSION: DSQFD is an effective preparation of traditional Chinese medicine for treating allergic rhinitis.