Search

The metal corrosion possesses a serious threat to the safety and loss of property. The anticorrosion study on metal-organic frameworks (MOFs) remains rarely reported. Therefore, it is desirable to build MOFs-based anticorrosion coating with long-term corrosion resistance. Herein, we prepared a novel MOF-polymer anticorrosion composite PANI@MIL-101 by encapsulating polyaniline (PANI) within the pores of MIL-101 with in-situ polymerization of aniline monomer. The N 2 adsorption-desorption and transmission electron microscopy (TEM) of PANI@MIL-101 illustrate that PANI is successfully encapsulated in the pores of MIL-101 with in-situ polymerization. PANI@MIL-101 was dispersed in epoxy resin (EP) to prepare anti-corrosive coatings. The Tafel potentiodynamic polarization measurements and electrochemical impedance spectroscopy show that PANI@MIL-101/EP coating system has superior corrosion protection with the lowest i corr value and the highest |Z| 0.01 value compared with MIL-101/EP coating, PANI/EP coating and EP coating. A possible anticorrosion mechanism of PANI@MIL-101 was discussed. This work reveals that MOF-polymer composite materials are superb candidates for high-performance corrosion protection. [ABSTRACT FROM AUTHOR]

Abstract Both epidemiological investigations and animal studies have linked arsenic-contaminated water to cancers, including skin, liver and lung cancers. Besides genotoxicity, arsenic exposure-related pathogenesis of disease is widely considered through epigenetic mechanisms; however, the underlying mechanism remains to be determined. Herein we explore the initial epigenetic changes via acute sodium arsenite (As) exposures of mouse embryonic fibroblast (MEF) cells and histone H3K79 methyltransferase Dot1L knockout (Dot1L−/−) MEF cells. Our RNA-seq and Western blot data demonstrated that, in both cell lines, acute As exposure abolished histone acetyltransferase p300 at the RNA level and subsequent protein level. Consequently, p300-specific main target histone H3K27ac, a marker separating active from poised enhancers, decreased dramatically as validated by both Western blot and ChIP-qPCR/seq analyses. Concomitantly, H3K4me1 as another well-known marker for enhancers also showed significant decreases, suggesting an underappreciated crosstalk between H3K4me1 and H3K27ac involved in As exposure. Significantly, As exposure-reduced H3K27ac and H3K4me1 inhibited the expression of genes including EP300 itself and Kruppel Like Factor 4(Klf4) that both are tumor suppressor genes. Collectively, our investigations identified p300 as an internal bridging factor within cells to sense external environmental As exposure to alter chromatin, thereby changing gene transcription for disease pathogenesis. Highlights • Acuate arsenite exposure abolished histone acetyltransferase p300. • A crosstalk between H3K4me1 and H3K27ac involved in arsenite exposure. • Attenuated H3K27ac and H3K4me1 repressed the expression of tumor suppressor genes upon arsenite exposure. [ABSTRACT FROM AUTHOR]

Abstract: Three-dimensional polyacrylamide gel microarray (3-D gel microarray) has a strong adsorption for hybridzation probes with fluorescent label, resulting in high fluorescent background noise. The background noise has hampered the broad application of the microarray in scientific research. A low-frequency ultrasound of 40kHz has been successfully employed to efficiently remove the nonspecifically bound fluorescent probes from the 3-D gel microarray. The method can significantly enhance the signal to noise ratio of the 3-D gel microarray and make it work better in single-nucleotide polymorphism genotyping. [Copyright &y& Elsevier]

[Display omitted] • Hollow CoVO x /Ag heterojunction was synthesized for OER. • The interaction of CoVO x and Ag nanoparticles regulated the electronic structure. • The extrinsic catalytic activity of CoVO x /Ag is enhanced due to the hollow structure. • The OER overpotential for CoVO x /Ag-5 at 10 mA cm−2 is only 247 mV. • The catalyst can enable full water splitting with 100% Faraday efficiency. Developing high-active and inexpensive electrocatalysts for oxygen evolution reaction (OER) is very important in the field of water splitting. The catalytic performance of electrocatalysts can be significantly improved by optimizing the electronic structure and designing suitable nanostructure. In this work, we represent the synthesis of hollow CoVO x /Ag-5 for OER. Due to the interaction of CoVO x and Ag nanoparticles, the electronic structure is optimized to improve the intrinsic catalytic activity. Additionally, the extrinsic catalytic activity of CoVO x /Ag is enhanced by the abundant active sites from the hollow structure. As a result, the CoVO x /Ag-5 demonstrates significantly enhanced OER catalytic activity with a low overpotential of 247 mV at 10 mA cm−2. In addition, it also exhibits excellent durability, without obvious attenuation in performance after continuous operation for 60 h. Furthermore, the catalyst can enable full water splitting with appropriate 100 % Faraday efficiency, demonstrating its practical application. [ABSTRACT FROM AUTHOR]

A novel CoMoO 4 -RuO 2 heterogeneous catalyst with flower-liked morphology was developed as a highly efficient bifunctional oxygen electrocatalyst for Zn-air battery. [Display omitted] Constructing heterogeneous catalysts can significantly boost the electrocatalytic activity due to the improved intrinsic catalytic activity induced by tailored electronic structure and optimized chemisorption to the reaction intermediates. RuO 2 based electrocatalysts are especially attractive due to the high catalytic activity of RuO 2. To reduce the usage of noble metal and improve the catalytic activity of catalyst, CoMoO 4 -RuO 2 micro-flower was synthesized using a facile hydrothermal-calcination method in this work. CoMoO 4 -RuO 2 exhibits a low overpotential of 177 mV at 10 mA cm−2 for oxygen evolution reaction (OER) and a high half-wave potential of 0.858 V for oxygen reduction reaction (ORR). Moreover, the Zn-air battery assembled using CoMoO 4 -RuO 2 exhibit shows a high maximum discharge power density of 149 mW cm−2 and a large open circuit voltage of 1.38 V. The good performance can be attributed to the incorporation of RuO 2 , which not only induces extra catalytic active sites, but also forms heterojunction with CoMoO 4 to optimize the electronic structure of CoMoO 4 -RuO 2 , thereby achieving a better equilibrium of absorption and desorption of intermediates. The work provides insights into designing RuO 2 based electrocatalysts for advanced electrocatalysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Single-atom Co catalysts with more Co-N 4 sites were successfully synthesized. • The catalyst exhibits an excellent ORR electrocatalytic activity. • The catalyst based Zn-air batteries shows higher peak power density. • DFT confirm that more Co-N 4 sites can lower the reaction energy barrier of ORR. Transition metal single atom catalysts (TM SACs) are the most promising oxygen reduction reaction (ORR) catalysts for proton exchange membrane fuel cells (PEMFCs) and metal-air batteries. However, the low density of M-N x active sites seriously hinders further improvement of the ORR electrocatalytic activity. Here, a strategy for encapsulating nitrogen-rich guest molecules (triethylenediamine cobalt complex, [Co(en) 3 ]3+) was proposed to construct a high-performance cobalt single-atom catalyst (Co-encapsulated SAC/NC). With this strategy, the guest molecules are encapsulated into metal–organic framework (MOF) cages as an additional cobalt source to boost cobalt loading, while abundant nitrogen from guest molecules contributes to the formation of Co-N 4 active sites. Remarkably, the resulting Co-encapsulated SAC/NC has a high cobalt loading amount of 4.03 wt%, and spherical aberration-corrected transmission electron microscopy (AC-TEM) has confirmed that most cobalt exists in a single-atom state. As a result, the Co-encapsulated SAC/NC exhibits excellent ORR catalytic performance with a half-wave potential of 0.88 V. Furthermore, Zn-air batteries employing Co-encapsulated SAC/NC as air cathode show high peak power density and excellent cycling stability. Density functional theory (DFT) calculations reveal that adjacent active sites have different rate-determining steps and lower reaction energy barriers than a single active site. [ABSTRACT FROM AUTHOR]

CoS 2 @MoS 2 @NiS 2 nano polyhedron with double-shelled structure was demonstrated to have multiple catalytic activity for HER, OER and ORR, which could serve as highly efficient catalysts for both rechargeable Zn-air batteries and overall water spitting. [Display omitted] • Double shelled hollow CoS 2 @MoS 2 @NiS 2 polyhedron was synthesized using a self-template method. • The CoS 2 @MoS 2 @NiS 2 exhibits multiple catalytic activity for HER, OER and ORR. • The CoS 2 @MoS 2 @NiS 2 exhibits a low HER overpotential of 156 mV at 10 mA cm−2. • The OER and ORR performance was demonstrated by rechargeable Zn-air battery. • The Zn-air battery can effectively drive water splitting device catalyzed by CoS 2 @MoS 2 @NiS 2. Electrocatalysts play important role in various energy conversion and storage devices. The catalytic performance of electrocatalysts can be enhanced through the increasement of intrinsic catalytic activity by optimizing electronic structure and the improvement of exposed active sites by designing proper nanostructures. In this work, CoS 2 @MoS 2 @NiS 2 nano polyhedron with double-shelled structure was prepared using metal organic framework as a precursor. Due to the rational integration of multifunctional active center, the strong electronic interaction of the various component, the high electrochemical surface area and shortened mass transport induced by the special structure, CoS 2 @MoS 2 @NiS 2 exhibits high catalytic activity for hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). Specifically, low overpotentials of 156 and 200 mV was achieved to deliver a current density of 10 mA cm−2 for HER and OER, and a high half-wave potential of 0.80 V was observed for ORR. More importantly, the Zn-air battery assembled by CoS 2 @MoS 2 @NiS 2 exhibits a high-power density of 80.28 mW cm−2 and could effectively drive overall water splitting. This work provides a new platform for designing multifunctional catalysts with high activity for energy conversion and storage. [ABSTRACT FROM AUTHOR]

Abstract: TiO2 nanoparticles have been widely explored as photocatalysts in the degradation of organic matters present in water. However, spontaneous agglomeration of TiO2 nanoparticles in a suspension is a crucial issue that must be addressed before the photocatalyst can be used for water treatment. In the present work, the nature of the agglomeration of TiO2 nanoparticles in aqueous suspension was investigated. Two approaches to minimize the agglomeration of colloidal TiO2 particles were investigated. A careful control over the pH of the system was found to be an effective method for stabilizing colloidal TiO2 particles and to significantly enhance the adsorption of orange II. As a result, the overall photocatalytic degradation rate was greatly accelerated. In addition to pH control, modification of TiO2 particles using polyelectrolyte poly allylamine hydrochloride (PAH) was observed to be an effective approach for preventing colloidal TiO2 particles from agglomeration. [Copyright &y& Elsevier]