Anchoring CeF3 nanoparticles on porous carbon nanofibers as self-supporting electrodes for highly sensitive detection of nitrite.

Designing a working electrode is crucial for the reliable electrochemistry detection, which is applied to detect toxic and harmful substances sensitively and rapidly. Here we report the polytetrafluoroethylene decomposition-assisted electrospinning, a combination method for creating nanopore and synthesizing CeF3, to prepare the self-supporting electrode of CeF3 nanoparticles-anchored on porous carbon nanofibers (CeF3/PCNFs) for highly sensitive nitrite detection. The CeF3/PCNFs exhibits remarkable electroactivity toward nitrite detection, featuring a wide concentration range (0.5 µM-6 mM), low detection limit (10 nm) and high sensitivity (2093 µA mM-1 cm-2). It also exhibits excellent selectivity, stability and reproducibility, and powerful reliability for nitrite detection in saliva, pickles, sausages, chips, river water and tap water. This study provides a facile strategy to prepare the metal fluoride-based self-supporting electrode, which overcomes the disadvantages of chemically modified electrodes unstable and poorly reproducible, and is significant for clinical diagnosis, food safety and environmental monitoring.

Review on strategies for improving the added value and expanding the scope of CO2 electroreduction products.

The electrochemical reduction of CO2 into value-added chemicals has been explored as a promising solution to realize carbon neutrality and inhibit global warming. This involves utilizing the electrochemical CO2 reduction reaction (CO2RR) to produce a variety of single-carbon (C1) and multi-carbon (C2+) products. Additionally, the electrolyte solution in the CO2RR system can be enriched with nitrogen sources (such as NO3-, NO2-, N2, or NO) to enable the synthesis of organonitrogen compounds via C-N coupling reactions. However, the electrochemical conversion of CO2 into valuable chemicals still faces challenges in terms of low product yield, poor faradaic efficiency (FE), and unclear understanding of the reaction mechanism. This review summarizes the promising strategies aimed at achieving selective production of diverse carbon-containing products, including CO, formate, hydrocarbons, alcohols, and organonitrogen compounds. These approaches involve the rational design of electrocatalysts and the construction of coupled electrocatalytic reaction systems. Moreover, this review presents the underlying reaction mechanisms, identifies the existing challenges, and highlights the prospects of the electrosynthesis processes. The aim is to offer valuable insights and guidance for future research on the electrocatalytic conversion of CO2 into carbon-containing products of enhanced value-added potential.

Interaction of pepper numbing substances with myofibrillar proteins and numbness perception under thermal conditions: A structural mechanism analysis.

This study examined the interaction between myofibrillar proteins (MPs) and the numbing substance hydroxy-α-sanshool (α-SOH) in a thermal environment, and provided an explanation of the numbness perception mechanism through muti-spectroscopic and molecular dynamics simulation methodology. Results showed that addition of α-SOH could reduce the particle size and molecular weight of MPs, accompanied by changes in the tertiary and secondary structure, causing the α-helix of MPs transitioned to ß-sheet and ß-turn due to the reorganization of hydrogen bonds. After a moderate heating (60 or 70 °C), MPs could form the stable complexes with α-SOH that were associated with attachment sites and protein wrapping. The thermal process might convert a portion of α-SOH' into hydroxy-ß-sanshool' (ß-SOH'). When docking with the sensory receptor TRPV1, the RMSD, RMSF and binding free energy all showed that ß-SOH' demonstrated a low affinity, thereby reducing the numbing perception. These findings can provide a theoretical foundation for the advanced processing of numbing meat products.

Arming Amorphous NiMoO4 on Nickel Phosphide Enables Highly Stable Alkaline Seawater Oxidation.

Seawater electrolysis holds tremendous promise for the generation of green hydrogen (H2 ). However, the system of seawater-to-H2 faces significant hurdles, primarily due to the corrosive effects of chlorine compounds, which can cause severe anodic deterioration. Here, a nickel phosphide nanosheet array with amorphous NiMoO4 layer on Ni foam (Ni2 P@NiMoO4 /NF) is reported as a highly efficient and stable electrocatalyst for oxygen evolution reaction (OER) in alkaline seawater. Such Ni2 P@NiMoO4 /NF requires overpotentials of just 343 and 370 mV to achieve industrial-level current densities of 500 and 1000 mA cm-2 , respectively, surpassing that of Ni2 P/NF (470 and 555 mV). Furthermore, it maintains consistent electrolysis for over 500 h, a significant improvement compared to that of Ni2 P/NF (120 h) and Ni(OH)2 /NF (65 h). Electrochemical in situ Raman spectroscopy, stability testing, and chloride extraction analysis reveal that is situ formed MoO4 2- /PO4 3- from Ni2 P@NiMoO4 during the OER test to the electrode surface, thus effectively repelling Cl- and hindering the formation of harmful ClO- .

Unravelling the interaction between α-SOH and myofibrillar protein based on spectroscopy and molecular dynamics simulation.

This work systematically investigated the dose-response interaction between hydroxy-α-sanshool (α-SOH) and pork myofibrillar proteins (MPs) via spectroscopy, molecular docking, and molecular dynamics simulation methods. Results showed that MPs bound with low α-SOH can enhance the surface hydrophobicity and particle size of MPs, whereas high concentrations were exactly the opposite. The main interaction force in α-SOH/MPs complex changed from hydrophobic to hydrogen bonding with increased α-SOH. α-SOH causes tryptophan quenching and bring about a red shift at low concentration, as well as to promote α-helix conversion into ß-sheet in MPs. Simultaneously, molecular docking and dynamics simulations verified that hydrogen bonding and hydrophobic forces were the main contributors to α-SOH/MPs complex, indicating that the binding of α-SOH with MPs proceeded spontaneously with high intensity, in which TYR286 contributed the most significant energy. Therefore, revealing the binding mechanism of α-SOH and MPs can contribute to the deep processing of numbing meat products.

HS-SPME-GC × GC/MS combined with multivariate statistics analysis to investigate the flavor formation mechanism of tank-fermented broad bean paste.

With the advancement of industrialization, tank fermentation technology is promising for Pixian broad bean paste. This study identified and analyzed the general physicochemical factors and volatile metabolites of fermented broad beans in a thermostatic fermenter. Headspace solid-phase microextraction (HS-SPME)-two-dimensional gas chromatography-mass spectrometry (GC × GC-MS) was applied to detect the volatile compounds in fermented broad beans, while metabolomics was used to explore their physicochemical characteristics and analyze the possible metabolic mechanism. A total of 184 different metabolites were detected, including 36 alcohols, 29 aldehydes, 26 esters, 21 ketones, 14 acids, 14 aromatic compounds, ten heterocycles, nine phenols, nine organonitrogen compounds, seven hydrocarbons, two ethers, and seven other types, which were annotated to various branch metabolic pathways of carbohydrate and amino acid metabolism. This study provides references for subsequent functional microorganism mining to improve the quality of the tank-fermented broad beans and upgrade the Pixian broad bean paste industry.

Enhanced removal performance of zero-valent iron towards heavy metal ions by assembling Fe-tannin coating.

Heavy metals (HMs) pose serious threats to both human and environmental health and therefore, effective and low-cost techniques to remove HMs are urgently required. Here we report a facile Fe-tannin coating method for zero-valent iron (ZVI) including nanoparticles (nZVI) and foam (Fefoam), and demonstrate that the generated Fe-tannin coating would remove the inherent passive iron oxide shell of ZVI and provide channels for the galvanic replacement reaction between ZVI and HM ions. Electrochemical characterizations demonstrate that the Fe core of the modified ZVI materials could be easily oxidized and transfer electrons to HM ions owing to the facile mass transport and charge transfer. In 40 min, nZVI@Fe-TA exhibits excellent performances for Cd(II), Ni(II), Pb(II), Hg(II), Cu(II) and Cr(VI) removal, with the apparent removal rate constants of 0.083, 0.085, 0.083, 0.073, 0.092 and 0.078 min-1, respectively. It is found that the surface area normalized rate constants of nZVI@Fe-TA are 4-7 times higher than that of nZVI@Fe2O3 counterpart, suggesting that the improved HM removal reactivity of nZVI@Fe-TA is derived from the surface modification. Moreover, nZVI@Fe-TA has advantages in resisting interference and in the simultaneous removal of different HM ions. Under a 30 min hydraulic retention time, Fefoam@Fe-TA could remove 98% HMs in the successive process. For real electroplating wastewater, Fefoam@Fe-TA exhibits excellent performance for Cr(VI) and Ni(II) removal, producing effluent of stable quality that meets local emission regulation. This study provides a facile strategy to remove the inherent passive iron oxide shell and enhance the HM removal reactivity for ZVI materials.

Co nanoparticle-decorated pomelo-peel-derived carbon enabled high-efficiency electrocatalytic nitrate reduction to ammonia.

Electrocatalytic nitrate reduction is a sustainable approach to produce ammonia and remediate water pollutant nitrate. Here, we show that Co nanoparticle-decorated pomelo-peel-derived carbon is an efficient electrocatalyst for nitrate reduction to ammonia with a faradaic efficiency of 90.1% and a yield of 1.1 mmol h-1 mgcat.-1.

Greatly Facilitated Two-Electron Electroreduction of Oxygen into Hydrogen Peroxide over TiO2 by Mn Doping.

Ambient electrochemical oxygen reduction into valuable hydrogen peroxide (H2O2) via a selective two-electron (2e-) pathway is regarded as a sustainable alternative to the industrial anthraquinone process, but it requires advanced electrocatalysts with high activity and selectivity. In this study, we report that Mn-doped TiO2 behaves as an efficient electrocatalyst toward highly selective H2O2 synthesis. This catalyst exhibits markedly enhanced 2e- oxygen reduction reaction performance with a low onset potential of 0.78 V and a high H2O2 selectivity of 92.7%, much superior to the pristine TiO2 (0.64 V, 62.2%). Additionally, it demonstrates a much improved H2O2 yield of up to 205 ppm h-1 with good stability during bulk electrolysis in an H-cell device. The significantly boosted catalytic performance is ascribed to the lattice distortion of Mn-doped TiO2 with a large amount of oxygen vacancies and Ti3+. Density functional theory calculations reveal that Mn dopant improves the electrical conductivity and reduces ΔG*OOH of pristine TiO2, thus giving rise to a highly efficient H2O2 production process.

Simultaneous determination of eight biogenic amines in the traditional Chinese condiment Pixian Douban using UHPLC-MS/MS.

A UHPLC-MS/MS method was developed to simultaneously determine eight biogenic amines (BAs) in Pixian Douban. Under optimal conditions, the linear ranges of determination were 5-1000 µg/L (that of spermine was 8-1000 µg/L). Correlation coefficients ranged from 0.9955 to 0.9987. The limits of detection were 0.11-5.5 µg/L. The matrix effect and analytical performance of the present method were evaluated, and the eight BAs were analyzed by this method in 19 samples, indicating the potential pollution of BAs in chili oil Pixian Douban.

Ultra-Stable Silica Nanoparticles as Nano-Plugging Additive for Shale Exploitation in Harsh Environments.

Owing to the harsh downhole environments, poor dispersion of silica at high salinity and high temperature can severely restrict its application as the nano-plugging agent in shale gas exploitation. The objective of this study is to improve salt tolerance and thermal stability of silica. Herein, silica was successfully functionalized with an anionic polymer (p SPMA) by SI-ATRP (surface-initiated atom transfer radical polymerization), named SiO2-g-SPMA. The grafted pSPMA brushes on silica provided sufficient electrostatic repulsion and steric repulsion for stabilizing silica in a harsh environment. The modified silica (SiO2-g-SPMA) had excellent colloidal stability at salinities up to 5.43 M NaCl (saturated brine) and standard API brine (8 wt% NaCl + 2 wt% CaCl2) for 30 days at room temperature. Simultaneously, the SiO2-g-SPMA was stable at 170 °C for 24 h as well as stable in weakly alkali environment. Furthermore, the plugging performance of SiO2-g-SPMA in water-based drilling fluids for low permeate reservoir reached to 78.25% when adding a small amount of 0.5 wt% SiO2-g-SPMA, which effectively hindered the water invasion into formation and protected the reservoir.

A base promoted one pot solvent free version of the Ramachary reductive coupling/alkylation reaction for the synthesis of 2,2-disubstituted ethyl cyanoacetates.

An N,N-diisopropylethylamine promoted solvent-free Ramachary reductive coupling/alkylation (RRC/A) reaction for the synthesis of 2,2-disubstituted ethyl cyanoacetates has been developed. A series of 2,2-disubstituted ethyl cyanoacetates were synthesized in one pot by the RRC/A reaction of commercially available aldehydes, ethyl cyanacetates, alkyl halides and Hantzsch ester. A solvent free two step multicomponent reaction has also been developed for the preparation of 2,2-dialkylated malononitriles and 2,2-dialkylated 4-nitrophenyl acetonitriles. All the designed RRC/A products could be easily obtained with good yields by these methods.

Poly[chlorido[µ(4)-2,2'-(2-methyl-1H-benzimidazol-3-ium-1,3-di-yl)diacetato]-zinc].

The title compound, [Zn(C(12)H(11)N(2)O(4))Cl](n), contains a centrosymmetric dimetal tetra-carboxyl-ate paddle-wheel moiety in which the Zn(II) atom is square-pyramidally coordinated by four carboxyl-ate O atoms at the basal positions and one Cl(-) anion at the apical position. Each paddle-wheel unit is joined to four such neighbours through bridging dicarboxyl-ate ligands, producing a two-dimensional undulating layer parallel to (-101). Adjacent sheets are stacked in a parallel fashion to form a three-dimensional supra-molecular structure which is stabilized by inter-layer π-π inter-actions between benzene rings, with a centroid-centroid distance of 3.722 Å. The range of Zn-O bond lengths is 2.0440 (17)-2.1256 (15) Šand the Zn-Cl bond length is 2.2622 (6) Å.

(1S*,5R*)-9-Phenyl-9-aza-bicyclo-[3.3.1]nonan-3-one.

In the title compound, C(14)H(17)NO, the piperidinone and piperidine rings both adopt a chair conformation. The chiral crystals were obtained from a racemic reaction product via spontaneous resolution.

Poly[di-µ(3)-chlorido-di-µ(2)-chlorido-{µ(4)-N,N,N',N'-tetra-kis-[(diphenyl-phosphan-yl)meth-yl]benzene-1,4-diamine-κ(4)P:P':P'':P'''}tetra-copper(II)].

In the title complex, [Cu(4)Cl(4)(C(58)H(52)N(2)P(4))](n), four Cu(II) atoms are held together via two doubly bridging and two triply bridging chlorides, forming a stair-like Cu(4)Cl(4) core having crystallographically imposed inversion symmetry, while the benzene-1,4-diamine ligand (with a crystallographic inversion center at the centroid) acts in a tetra-dentate coordination mode, bridging two adjacent Cu(4)Cl(4) cores, resulting in a chain along the a-axis direction. One Cu atom has a distorted tetra-hedral geometry, coordinated by one P atom, one µ(2)-Cl and two µ(3)-Cl atoms, while the second Cu atom adopts a trigonal geometry, coordinated by one P atom, one µ(2)-Cl and one µ(3)-Cl atoms.

Synthesis, X-ray crystal structure and optical properties of novel 5-(3-aryl-1H-pyrazol-5-yl)-2-(6-methoxy-3-methylbenzofuran-2-yl)-1,3,4-oxadiazole.

A series of novel 5-(3-aryl-1H-pyrazol-5-yl)-2-(6-methoxy-3-methylbenzofuran-2-yl)-1,3,4-oxadiazole derivatives has been synthesized from 6-methoxy-3-methylbenzofuran-2-carboxylic acid and ethyl 3-aryl-1H-pyrazole-5-carboxylate. The structures of compounds obtained were determined by IR, (1)H NMR and HRMS spectra. Typically, the spatial structure of compound 7e was determined by using X-ray diffraction analysis. UV-vis absorption and fluorescence spectral characteristics of the compounds in dichloromethane and acetonitrile were investigated. The results showed that the absorption maxima of the compounds vary from 321 to 339 nm depending on the substituents in N-1 position of pyrazole moiety and para position of benzene moiety. The maximum emission spectra of compounds in two different solvents were mainly dependent on groups in N-1 position of pyrazole moiety. The intensity of absorption and fluorescence was also correlated with substituents on the aryl ring bonded to pyrazole moiety. In addition, the absorption and emission spectra of these compounds change with increasing solvent polarity.