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Synthesis of formate from hydrogenation of carbon dioxide (CO2) is an atom‐economic reaction but is confronted with challenges in developing high‐performance non‐precious metal catalysts for application of the process. Herein, we report a highly durable edge‐rich molybdenum disulfide (MoS2) catalyst for CO2 hydrogenation to formate at 200 °C, which delivers a high selectivity of over 99 % with a superior turnover frequency of 780.7 h−1 surpassing those of previously reported non‐precious metal catalysts. Multiple experimental characterization techniques combined with theoretical calculations reveal that sulfur vacancies at MoS2 edges are the active sites and the selective production of formate is enabled via a completely new water‐mediated hydrogenation mechanism, in which surface OH* and H* species in dynamic equilibrium with water serve as moderate hydrogenating agents for CO2 with residual O* reduced by hydrogen. This study provides a new route for developing low‐cost high‐performance catalysts for CO2 hydrogenation to formate. [ABSTRACT FROM AUTHOR]

Synthesis of formate from hydrogenation of carbon dioxide (CO2) is an atom‐economic reaction but is confronted with challenges in developing high‐performance non‐precious metal catalysts for application of the process. Herein, we report a highly durable edge‐rich molybdenum disulfide (MoS2) catalyst for CO2 hydrogenation to formate at 200 °C, which delivers a high selectivity of over 99 % with a superior turnover frequency of 780.7 h−1 surpassing those of previously reported non‐precious metal catalysts. Multiple experimental characterization techniques combined with theoretical calculations reveal that sulfur vacancies at MoS2 edges are the active sites and the selective production of formate is enabled via a completely new water‐mediated hydrogenation mechanism, in which surface OH* and H* species in dynamic equilibrium with water serve as moderate hydrogenating agents for CO2 with residual O* reduced by hydrogen. This study provides a new route for developing low‐cost high‐performance catalysts for CO2 hydrogenation to formate. [ABSTRACT FROM AUTHOR]

The root of Panax ginseng C. A. Mey (Araliaceae) has medicinal value in complex system of Traditional Chinese medicines for its use in improving cognitive function. A glycoproteins named PGL-1 was extracted from ginseng which subjected to through a macroporous resin, hollow-fiber ultrafiltration and dialyzed. The glycoproteins has a molecular weight in the range from 0.4 to 4.4 kDa, with an average molecular mass of 1.6 kDa. HPLC analysis revealed that the compositions of glycoproteins included fucose, mannose, rhamnose, glucose, galacturonic acid, N -acetylglucosamine and N -acetylgalactosamine. Glycan of PGL-1 has a backbone of →4)-Rha-(1→, →4)-Fuc -(1→, →6)-Gal-(1→, →4)-GalA-(1→, →4)-GlcNAc-(1→ and →4)-GalNAc-(1→,and (→3,6)-Man-(1→) was distributed in branches. The (1→)-Fuc, (1→)-Glc and (1→)-GlcNAc or (1→)-GalNAc were regarded as a terminal residue. The Morris water maze test revealed that the PGL-1 can effectively alleviate the memory impairment symptoms of rats induced by Aβ 25–35 . All dose groups showed significant activity of protective effect on apoptosis SH-SY5Y induced by Aβ 25–35 , and obviously inhibited the S phase arrest. Compared with Aβ 25–35 treatment alone, a significant reduction in NO concentration and NOS activity was detected in cells co-administered with glycoproteins. Thus, glycoproteins derived from ginseng might be a promising anti-AD reagent. [ABSTRACT FROM AUTHOR]

In this study we propose a simple and sensitive colorimetric aptasensor for the quantitative analysis of abrin by using catalytic AuNPs for the first time. AuNPs possess the peroxidase-like activity that can catalyse 3,3,5,5-tetramethylbenzidine (TMB) in the presence of H2O2, leading to color change of the solution. It is interesting to find that the peroxidase-like activity of AuNPs can be improved by surface activation with a target-specific aptamer. However, with a target molecule, the aptamer is desorbed from the AuNPs surface, resulting in a decrease of the catalytic abilities of AuNPs. The color change of the solution is relevant to the target concentration, and this can be judged by the naked eye and monitored by using a UV-vis spectrometer. The linear range for the current analytical system was from 0.2 nM to 17.5 nM. The corresponding limit of detection (LOD) was 0.05 nM. Some other proteins such as thrombin (Th), glucose oxidase (GOx), and bovine serum albumin (BSA) all had a negligible effect on the determination of abrin. Furthermore, several practical samples spiked with abrin were analyzed using the proposed method with excellent recoveries. This aptamer-based colorimetric biosensor is superior to other conventional methods owing to its simplicity, low cost, and high sensitivity. [ABSTRACT FROM AUTHOR]

Abstract: A new approach has been developed for the functionalization of multi-walled carbon nanotubes (MWNTs). The self-assembly of a sugar-based amphiphile on MWNTs was carried out in amino acid solutions. The functionalization of MWNTs has been investigated by means of UV–vis, Raman spectra, FTIR, XPS, XRD, and HRTEM. It has been found that amino acids can promote the self-assembly of the amphiphile on MWNTs and regulate the amount and conformation of the assembled amphiphile. The effect of amino acids on the aggregation of the sugar-based amphiphile on MWNTs was analyzed through FTIR spectra. The specific interactions of f-MWNTs with the protein concanavalin A were investigated through the measurement of UV–vis spectra. This work demonstrates that, the functionalized MWNTs with disaccharide groups on their exterior surface have a good dispersibility in water and are biocompatible, and may have a potential application of biomolecular recognition. [Copyright &y& Elsevier]

Keywords: Carbon Dioxide Conversion; Heterogeneous Catalysis; Materials Science; Reaction Mechanisms; Reduction EN Carbon Dioxide Conversion Heterogeneous Catalysis Materials Science Reaction Mechanisms Reduction 1 1 1 10/31/23 20231106 NES 231106 B CO SB 2 sb hydrogenation to formate b is an attractive route for the utilization of this greenhouse gas. Comprehensive mechanism studies reveal that selective production of formate is enabled at MoS SB 2 sb edge sulfur vacancies via a new water-mediated hydrogenation mechanism. Carbon Dioxide Conversion, Heterogeneous Catalysis, Materials Science, Reaction Mechanisms, Reduction. [Extracted from the article]

Keywords: Carbon Dioxide Conversion; Heterogeneous Catalysis; Materials Science; Reaction Mechanisms; Reduction EN Carbon Dioxide Conversion Heterogeneous Catalysis Materials Science Reaction Mechanisms Reduction 1 1 1 10/31/23 20231106 NES 231106 B Sn-based perovskite oxides b have shown intriguing potential in CO SB 2 sb electroreduction. Carbon Dioxide Conversion, Heterogeneous Catalysis, Materials Science, Reaction Mechanisms, Reduction In their Research Article (e202307086), Jiawei Zhu and co-workers report an effective strategy to promote CO SB 2 sb -to-HCOOH conversion of Sn-based perovskite oxides by A-site-radius-controlled Sn-O bond lengths. [Extracted from the article]

Bupleurum chinense DC. (B. chinense) is the dried root of B. chinense , belonging to the Umbelliferae family. B. chinense has been reported since ancient times for its effect of soothing the liver and relieving depression. Additionally, its important role in treating depression, depressed mood disorders and anti-inflammation has been proven in previous studies. However, its specific mechanism of action remains unknown. The key targets and metabolites of the antidepressant effect of B. chinense were investigated based on the cAMP signalling pathway. The study examined the mechanism for the antidepressant effect of B. chinense by target prediction, analysis of related metabolites and potential metabolic pathways. A network pharmacology approach was used to predict the antidepressant targets and pathways of B. chinense. A depression rat model was established through the CUMS (chronic unpredictable mild stress) procedure. The depression model was assessed by body weight, sugar-water preference, water maze and enzyme-linked immunosorbent assay (ELISA) indicators (5hydroxytryptamine, etc.). The key metabolic pathways were screened by correlations between metabolites and key targets. Finally, a quantitative analysis of key targets and metabolites was experimentally validated. B. chinense significantly ameliorated the reduction in body weight, sugar-water preference rate and cognitive performance in the water maze experiment in rats with depression induced by CUMS. ELISA, Western blotting (WB) and reverse transcription-polymerase chain reaction (RT-PCR) assays showed that B. chinense significantly improves the expression of protein kinase cyclic adenylic acid (cAMP)-activated catalytic subunit alpha (PRKACA), cAMP-response element-binding protein (CREB) and cAMP activation in the rat brain induced by CUMS. According to metabolic pathway analysis, B. chinense shows an antidepressant effect primarily by regulating the cAMP metabolic pathway. B. chinense upregulated PRKACA and CREB expression and the level of the key metabolite cAMP in the cAMP/PKA/CREB pathway while reducing the inflammatory response to depression treatment. These new findings support future research on the antidepressant effects of B. chinense. [Display omitted] • Bupleurum chinense DC. could restore the expression of PRKACA, CREB. • B.chinense could significantly increase the content of metabolite cAMP. • B.chinense could regulate the imbalance of cAMP/PKA/CREB signalling pathway. [ABSTRACT FROM AUTHOR]

Highlights • EG/CuO@C is prepared by self-combustion and hydrothermal treatment. • The model of EG/CuO@C structure explain the electrochemical performance. • The EG/CuO@C has the excellent capacitance. Abstract Expanded graphite embedded with CuO nanospheres coated with carbon (EG/CuO@C) is in-situ prepared by self-combustion and hydrothermal treatment methods The component analysis of the composite is carried out using X-ray diffraction and its morphology and microstructure are characterized using field emission scanning electron microscopy (FESEM) and transmission electron microscope (TEM). The electrochemical performance is examined by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy in 6 M KOH solution as electrolyte. The experimental results revealed that the EG/CuO@C composite remained porous structure, which is beneficial for supercapacitance. The EG/CuO@C exhibits the high specific capacitance of 335 F g−1 and the capacitance retention of 87% after 8000 cycles at the scan rate of 10 mV s−1. Moreover, the EG/CuO@C composite remains high energy density of 14.03 Wh kg−1 at the power density of 10.1 kW kg−1. [ABSTRACT FROM AUTHOR]

In this work, a facile approach to sensitively detect sulfide ions is developed. The proposed method is based on the findings that silver ions could oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) to induce a blue color and an absorption peak centered at 652 nm. The introduction of sulfide ions leads to the formation of Ag 2 S nanoparticles which act as catalyst to enhance the oxidation capacity of silver ions, resulting in a blue color burning and increase of the absorbance at 652 nm. Based on the above facts, a facile method is developed to qualitatively and quantitatively detect sulfide ions by naked eyes and UV–vis spectroscopy, respectively. The color changes of the detection system in the presence of nanomolar level of sulfide ions could be distinguished by naked-eyes, demonstrating the high sensitivity of the method. Highly sensitive detection of sulfide ions can be achieved in the range of 1.0 × 10 −9 M to 8.0 × 10 −8 M, with a detection limit of 0.2 nM. In addition, this method shows excellent selectivity toward sulfide ions detection and has been successfully applied to detect sulfide ions in tap water and lake water samples. Moreover, this method is simple without the preparation of nanomaterials and the need of complex readout instruments. [ABSTRACT FROM AUTHOR]

In this paper, a novel biosensor based on Carbon dots (C-dots) for sensitive detection of hydroquinone (H 2 Q) is reported. It is interesting to find that the fluorescence of the C-dots could be quenched by H 2 Q directly. The possible quenching mechanism is proposed, which shows that the quenching effect may be caused by the electron transfer from C-dots to oxidized H 2 Q-quinone. Based on the above principle, a novel C-dots based fluorescent probe has been successfully applied to detect H 2 Q. Under the optimal condition, detection limit down to 0.1 μM is obtained, which is far below U.S. Environmental Protection Agency estimated wastewater discharge limit of 0.5 mg/L. Moreover, the proposed method shows high selectivity for H 2 Q over a number of potential interfering species. Finally, several water samples spiked with H 2 Q are analyzed utilizing the sensing method with satisfactory recovery. The proposed method is simple with high sensitivity and excellent selectivity, which provides a new approach for the detection of various analytes that can be transformed into quinone. [ABSTRACT FROM AUTHOR]

It’s almost hardly to realize the large-scale practical application of fuel cells if the costly noble metal-based electrocatalysts for oxygen reduction reaction (ORR) cannot be replaced by other efficient, stable, and low-cost non-precious metal or even metal-free ORR electrocatalysts. Herein, we report the novel design and synthesis of N and S dual-doped hierarchical micro/mesoporous carbon (NS-MC) foams via high temperature treatment of polyaniline coated sulfur sphere composite without any side products. The highlight of our method lies in its environmental concept of green synthesis and simplicity for no use of toxic gas (NH 3 or H 2 S) or templates (SiO 2 or MgO). The main focus of this research is to develop a high-performance metal-free ORR electrocatalyst as well as to gain insight into the synergistic effects originating from multiple-element doping on ORR performance. It is found that much graphitic-N and thiophene-S binding configurations formed for NS-MC foams at 1000 °C, which shows excellent electrocatalytic activity (high onset potential (0.051 V vs. Ag/AgCl (sat.KCl)), large diffusion-limiting current density (5.61 mA cm −2 at 1600 rpm) and kinetic current density (22.22 mA cm −2 at −0.25 V)), high selectivity towards methanol and long durability compared to commercial Pt/C with a nearly four-electron transfer passway when they are employed as metal-free catalyst for ORR. Besides, the desired NS-MC1000 shows a strong amperometric response towards ethanol indicating its potential application as an anode metal-free electrocatalyst in the alkaline direct ethanol fuel cell. [ABSTRACT FROM AUTHOR]

In this work, a novel facile nanoparticle autocatalytic sensor based on the inhibition of the Ag autocatalytic reaction for the determination of Hg2+ was developed. o-Phenylenediamine (OPD) tended to be oxidized into 2,3-diaminophenazine (OPDox) by silver ions (Ag+) followed by the formation of silver nanoparticles (AgNPs). Employed as a catalyst, the thus-formed AgNPs would further promote the reaction between OPD and Ag+. When Hg2+ was introduced, Hg2+ adsorbed on the surface of the AgNPs, thus inhibiting the oxidation process mentioned above and achieving weakened fluorescence intensity. A linear relationship between fluorescence intensity and Hg2+ concentration (within the range from 10 nM to 2500 nM) was obtained and the detection limit reached as low as 8.2 nM. The proposed method was also applied for the determination of Hg2+ in real water samples with satisfactory results. The protocol showed excellent advantages of sensitivity and selectivity for Hg2+ over various metal ions and anions. Meanwhile, this method was simpler and more cost-effective compared with many reported nanomaterial- and DNA-based approaches. Furthermore, an “INHIBIT” logic gate based on the Ag+–Hg2+–OPD system has also been designed. [ABSTRACT FROM AUTHOR]

Glutathione (GSH) plays an important role in the biological system and serves many cellular functions. Since all of the biothiols possess similar functional groups, it is still challenging to selectively detect GSH over cysteine (Cys) and homocysteine (Hcy). In this work, a novel and simple colorimetric method for discriminative detection of glutathione (GSH) over Cys and Hcy is developed. The proposed method is based on the fact that Ag [I] ion could oxidize 3,3′,5,5′,-tetramethylbenzidine (TMB) to the oxidized TMB to induce a blue color and an absorption peak centered at 652 nm. However, the introduction of GSH could cause the reduction of oxidized TMB and it could also combine with Ag + , both of which result in a blue color fading and a decrease of the absorbance at 652 nm. Based on this finding, we propose a method to qualitatively and quantitatively detect GSH by naked eyes and UV–vis spectroscopy, respectively. The proposed method shows a low detection limit of 0.1 µM by naked eyes and 0.05 µM with the help of UV–vis spectroscopy. In addition, this method has great potential in discriminatively detecting GSH over other amino acid and biothiols. More importantly, this method is simple and fast without the preparation of nanomaterials and has also been successfully applied to the detection of GSH in biological fluids. [ABSTRACT FROM AUTHOR]

Abstract: In this study, a facile method to sensitively detect melamine and highly improve the peroxidase-like activity of bare gold nanoparticles (Au NPs) at the same time is proposed for the first time. It is interesting to find that the addition of melamine could improve the peroxidase-like activity of Au NPs. By coupling with 3,3′,5,5′-tetramethlybenzidine (TMB)–H2O2 chormogenic reaction, a novel method for colorimetic detection of melamine is developed. The detection limit of this method is as low as 0.2nM with the help of UV–vis spectroscopy and 0.5µM by naked-eye observation, both which are far below the US food and Drug Administration estimated melamine safety limit of 20µM. In addition, the present method is successfully applied for the detection of melamine in raw milk and milk powder. More importantly, the proposed method could also improve the peroxidase-like activity of Au NPs, which may not only provide a new approach to develop effective nanomaterials-based mimetic enzyme, but also irradiative to develop new applications for Au NPs in varieties of cost-effective and simple sensors in medicine, biotechnology and environmental chemistry. [Copyright &y& Elsevier]

In this work, we proposed a facile, environmentally friendly and cost-effective assay for melamine with BSA-stabilized gold nanoclusters (AuNCs) as a fluorescence reader. Melamine, which has a multi-nitrogen heterocyclic ring, is prone to coordinate with Hg2+. This property causes the anti-quenching ability of Hg2+ to AuNCs through decreasing the metallophilic interaction between Hg2+ and Au+. By this method, detection limit down to 0.15µM is obtained, which is approximately 130 times lower than that of the US food and Drug Administration estimated melamine safety limit of 20µM. Furthermore, several real samples spiked with melamine, including raw milk and milk powder, are analyzed using the sensing system with excellent recoveries. This gold-nanocluster-based fluorescent method could find applications in highly sensitive detection of melamine in real samples. [ABSTRACT FROM AUTHOR]

Abstract: NiCo2O4 nanoflake composites were synthesized by using DNA molecules as templates via in-situ assembly and subsequent thermal treatment. The obtained NiCo2O4 composites were characterized by scanning electron microscopy, energy dispersive spectroscopy, X-ray powder diffraction, thermogravimetric analysis, and X-ray photoelectron spectroscopy. Cyclic voltammetry and chronopotentiometry tests were used to investigate the electrochemical properties of the as-prepared composites. Superior performances with a good specific capacitance (1468 F/g), an extraordinary rate capability (64.9% capacity retention at 16 A/g) and an excellent cycling stability (85.5% retention after 5000 cycles) were achieved. The DNA templates were introduced as the binder of NiCo2O4 and as the conductive matrix to facilitate the electron transmission between electroactive materials and outside current collectors, which resulted in the excellent electrochemical performances of the synthesized NiCo2O4 composites. It is believed that our NiCo2O4 nanocomposites could be used as effective electrode materials for supercapacitors. [Copyright &y& Elsevier]

This study demonstrates a cocaine sensing method employing graphene oxide (GO), gold nanoparticles and a structure switching aptamer, which can fold into a three-way junction in the presence of cocaine. On the observation of gold nanoparticles (Au NPs) induced graphene oxide fluorescence quenching, a structure switching aptamer of cocaine was introduced as the linker between the two parts. Firstly, two fragments of a cocaine aptamer were immobilized covalently onto GO and Au NPs, respectively. Then when the three-way junction formed, the Au NPs were drawn near to the GO surface and induced a fluorescence intensity decrease. The limit of detection was 0.1 μM for cocaine in purified water, and well defined results were also obtained in biological fluids and the specificity experiment, which expands the feasibility of the as-prepared sensor for practical applications. [ABSTRACT FROM AUTHOR]

Abstract: Here, we report a new and facile method to prepare silver nanoparticles (Ag NPs) film for surface-enhanced Raman scattering (SERS)-based sensing. The porous Ni foam was used as a template to generate high quality of Ag NPs by seed-mediated growth of metallic nanoparticles. The preparation process is very economic and environment-friendly, can achieve the recovery of the raw materials. We found that the type of silver-plating solution and the growth time are two key factors to determine the magnitude of SERS signal enhancement. Using rhodamine 6G (R6G) and 4-animothiophenol (4-ATP) as probe molecules, the created Ag NP films exhibited relatively high enhancement ability, good stability, and well reproducibility. The synthesized SERS-active substrate was further used to detect melamine molecules, an illegal additive in infant milk powder, and the limitation of detection can reach 1μM. [Copyright &y& Elsevier]

Electrochemical reduction and electrodeposition are two effective methods for the preparation of new nanomaterials for electrochemical sensing. In this work, the reduced graphene oxide-nickel nanoparticles composite (RGO-NiNPs) was synthesized using both methods mentioned above. The fabrication process was simple and easily performed. Then, the RGO-NiNPs composite was characterized by SEM, EDS, and XRD. Furthermore, for the strong catalytic ability of the high-valent oxyhydroxide species (NiOOH) formed in alkaline media, the composite was used as the matrix for nonenzymatic detection of glucose. Comparing with NiNPs modified glassy carbon electrode (NiNPs/GCE), the RGO-NiNPs/GCE showed better sensitivity and stability. A low detection limit of 0.1 µM with a wide linear range from 2 µM to 2.1 mM ( R=0.996) was obtained. [ABSTRACT FROM AUTHOR]

Abstract: An alkoxysilane precursor based on imidazole chromophore, namely 2-((4-(ethyl(2-hydroxyethyl)amino)phenyl)diazenyl)-4,5-dicyano-1H-imidazole (IZ), has been successfully synthesized through a urethane forming reaction. Following a sol–gel process of the resultant precursor, inorganic–organic hybrid films were obtained by spin-coating. Their structures were verified by 1H NMR, FT-IR, UV–vis spectra and elemental analysis. After corona poling, the electro-optic (EO) properties of the hybrid films were characterized by a simple reflection technique, and the EO coefficient (r 33) of a sample was determined to be 1.6pm/V at a wavelength of 1310nm. [Copyright &y& Elsevier]