Rational design of hollow flower-like MoS2/Mo2C heterostructures in N-doped carbon substrate for synergistically accelerating adsorption-electrocatalysis of polysulfides in lithium sulfur batteries.

Lithium-sulfur (Li-S) batteries have been garnered significant attention in the energy storage field due to their high theoretical specific capacity and low cost. However, Li-S batteries suffer from issues like the shuttle effect, poor conductivity, and sluggish chemical reaction kinetics, which hinder their practical development. Herein, a novel hollow flower-like architecture composed of MoS2/Mo2C heterostructures in N-doped carbon substrate (H-Mo2S/Mo2C/NC NFs), which were well designed and prepared through a calcination-vulcanization method, were used as high-efficiency catalyst to propel polysulfide redox kinetics.Ex situelectrochemical impedance spectroscopy verify that the abundant heterojunctions could facilitate electron and ion transfer, revealed the excellent interface solid-liquid-solid conversion reaction. The adsorption test of Li2S6showed that Mo2S and Mo2C formed heterostructure generate the binding of polysulfide could be enhanced. And cyclic voltammetry test indicate boost the polysulfide redox reaction kinetics and ion transfer of H-Mo2S/Mo2C/NC/S NFs cathode. Benefiting from the state-of-the-art design, the H-Mo2S/Mo2C/NC/S NFs cathode demonstrates remarkable rate performance with a specific capacity of 1351.9 mAh g-1at 0.2 C, when the current density was elevated to 2 C and subsequently reverted to 0.2 C, the H-Mo2S/Mo2C/NC/S NFs cathode retained a capacity of 1150.4 mAh g-1, and it maintains exceptional long cycling stability (840 mA h g-1at 2 C after 500 cycles) a low capacity decay of 0.0073% per cycle. This work presents an effective approach to rapidly fabricating multifunctional heterostructures as an effective sulfur host in improving the polysulfide redox kinetics for lithium sulfur batteries.

Self-Adaptive Electronic Structure of Amphoteric Conjugated Ligand-Modified 3 d Metal-C3 N4 Smart Electrocatalyst by pH Self-Response Realizing Electrocatalytic Self-Adjustment.

Constructing pH-responsive smart material provides a new opportunity to address the problem that traditional electrocatalysts cannot achieve both alkaline oxygen evolution reaction (OER) and acidic hydrogen evolution reaction (HER) activities. In this study, amphoteric conjugated ligand (2-aminoterephthalic acid, BDC-NH2 )-modified 3d metal-anchored graphitic carbon nitride (3d metal-C3 N4 ) smart electrocatalysts are constructed, and self-adaptation of the electronic structure is realized by self-response to pH stimulation, which results in self-adjustment of alkaline OER and acidic HER. Specifically, the amino and carboxyl functional groups in BDC-NH2 undergo protonation and deprotonation respectively under different pH stimulation to adapt to environmental changes. Through DFT calculations, the increase or decrease of electron delocalization range brought by the self-response characteristic is found to lead to redistribution of the Bader charge around the modified active sites. The OER and HER activities are greatly promoted roughly 4.8 and 8.5 times over Co-C3 N4 after BDC-NH2 -induced self-adaptive processes under different environments, arising from the reduced energy barrier of O* to OOH* and ΔGH* . Impressively, the proposed BDC-NH2 -induced smart regulation strategy is applicable to a series of 3d metal anchors for C3 N4 , including Co, Ni and Fe, providing a general structural upgrading method for constructing smart electrocatalytic systems.

Biocatalyst and colorimetric biosensor of carcinoembryonic antigen constructed via chicken egg white-copper phosphate organic/inorganic hybrid nanoflowers.

In this article, the dual-functional chicken egg white-copper phosphate organic-inorganic hybrid nanoflowers (Cu-NFs), combining the functions of signal amplification and biological recognition, were prepared through a simple one-pot method. The Cu-NFs exhibit excellent biocatalytic activity of peroxidase and polyphenol oxidase. Besides, a biotin-labeled secondary antibody encapsulated Cu-NFs-2 (Cu-NFs-2@Biotin-NHS-Ab2) capture probe was prepared by using the interaction between avidin in the egg white and biotin. Based upon this superiority, the as-prepared Cu-NFs-2 were used in labeled avidin-biotin enzyme-linked immunosorbent assay (Cu-NFs-2 based-LAB-ELISA) to construct a sensitive colorimetric biosensor for the ultrasensitive detection of carcinoembryonic antigen (CEA). Under weak alkaline (pH = 7.5) conditions, the as-developed colorimetric sensor displayed a wide linear range of 0.05-40 ng/mL with a detection limit of 3.52 pg/mL. Furthermore, this colorimetric sensor has been successfully applied to the detection of CEA in human serum samples. Therefore, the as-developed colorimetric sensor has broad application prospects in the field of medical diagnosis and portable detection.

Synthesis, Characterization and Optoelectronic Property of Axial-Substituted Subphthalocyanines.

Two novel substituted subphthalocyanines have been prepared introducing m-hydroxybenzoic acid and m-hydroxyphenylacetic acid into the axial position of bromo-subphthalocyanine. The compounds have been characterized by Fourier transform infrared (FT-IR), Nuclear Magnetic Resonance (NMR) and single-crystal X-rays diffraction (XRD) methods. Their photophysical properties show that the axial substitution results into a relatively higher fluorescence quantum efficiency (ΦF=5.74 for m-hydroxybenzoic acid and 9.09 % for m-hydroxyphenylacetic acid) in comparison with that of the prototype compound, despite the almost negligible influence on the maximum absorption or the emission position. Moreover, the electrochemical behaviors show that the axial-substituted subphthalocyanines also exhibit enhanced specific capacitances of 395 F/g (m-hydroxybenzoic acid) and 362 F/g (m-hydroxyphenylacetic acid) compared with 342 F/g (the prototype) to the largest capacitance at the scan rate of 5 mV/s, and the significantly larger capacitance retentions of 83.6 % and 82.1 % versus 37.3 % upon density up to 3 A/g. These results show the potential of these axial-substituted subphthalocyanines in the use as organic photovoltaics and supercapacitors.

Enhanced Electrocatalytic Performance through Body Enrichment of Co-Based Bimetallic Nanoparticles In Situ Embedded Porous N-Doped Carbon Spheres.

Extending available body space loading active species and controllably tailoring the d-band center to Fermi level of catalysts are of paramount importance but extremely challenging for the enhancement of electrocatalytic performance. Herein, a melamine-bridged self-construction strategy is proposed to in situ embed Co-based bimetallic nanoparticles in the body of N-doped porous carbon spheres (CoM-e-PNC), and achieve the controllable tailoring of the d-band center position by alloying of Co and another transition metal M (M = Ni, Fe, Mn, and Cu). The enrichment and exposure of the active sites in the body interior of porous carbon spheres, and the best balance between the adsorption of OH species and the desorption of O2 induced by optimizing the d-band center position, collectively enhance the oxygen evolution reaction (OER) performance. Meanwhile, the relationship of d-band center position and OER activity is found to exhibit the volcano curve rule, where the CoNi-e-PNC catalyst shows optimal OER performance with an overpotential of 0.24 V at 10 mA cm-2 in alkaline media, outperforming those of the ever-reported CoNi-based catalysts. Besides, CoNi-e-PNC catalyst also demonstrates high OER stability with slight current decrease after 100 h.

Controlling the Chemical Bonding of Highly Dispersed Co Atoms Anchored on an Ultrathin g-C3N4@Carbon Sphere for Enhanced Electrocatalytic Activity of the Oxygen Evolution Reaction.

Controlling the chemical bonding of an active atom and carbon support is an effective strategy for enhancing the electrocatalytic activity of a metal-nitrogen/carbon catalyst. Herein, highly dispersed Co atoms are successfully prepared by using an ultrathin g-C3N4@carbon sphere as the support, and subsequently the well-defined Co-N and Co-O bonds on the atomic level are controllably constructed by adjusting the calcination atmosphere. Results show that highly dispersed Co with Co-O and Co-N bonds exhibits excellent oxygen evolution reaction performance in alkaline media at low and high overpotentials, respectively, and outperform most single-atom catalysts reported to date. DFT calculation, coupled with high-angle annular dark-field scanning transmission electron microscopy and X-ray photoelectron spectrometry techniques, reveals that the high activities mainly originate from the precise O-Co-N and N-Co-N coordination in the ultrathin g-C3N4@carbon sphere support. The enhancement mechanism of chemical bonding provides guidance for the atomic exploration and design of electrocatalysts.

Biocatalyst and Colorimetric/Fluorescent Dual Biosensors of H2O2 Constructed via Hemoglobin-Cu3(PO4)2 Organic/Inorganic Hybrid Nanoflowers.

In this article, the three-dimensional hemoglobin (Hb)-Cu3(PO4)2 organic/inorganic hybrid nanoflowers (Hb-Cu3(PO4)2 HNFs) self-assembled by nanopetals were synthesized via a facile one-pot green synthetic method. The compositions and microstructure of the Hb-Cu3(PO4)2 HNFs were well-characterized with X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and UV-vis spectrometry, respectively. The as-prepared Hb-Cu3(PO4)2 HNFs were to be used as a biocatalyst to construct colorimetric/fluorescent dual biosensors. The experimental results show that the colorimetric/fluorescent dual biosensors exhibited two linear responses in the range of 2-10 ppb and 20-100 ppb for H2O2. The colorimetric and fluorescent detection limits were 0.1 and 0.01 ppb, respectively. Compared with the free Hb, the biocatalytic activity of the Hb-Cu3(PO4)2 HNFs can be improved for 3-4 times under optimal conditions. The sensing performance of these Hb-Cu3(PO4)2 HNF-based dual biosensors can be contributed such that the active sites of Hb molecules were more exposed on the surface of the Cu3(PO4)2 nanopetals. Second, the unique nanopetal-assembled hybrid flowerlike structure was favorable to contact the detected substance with the biosensors. The dual biosensors were successfully applied for the determination of H2O2 in rainwater, tap water, and waste water samples. These results show that the dual biosensors had a potential application in the field of medical analysis, environmental monitoring, and food engineering.

Two porous luminescent metal-organic frameworks: quantifiable evaluation of dynamic and static luminescent sensing mechanisms towards Fe(3.).

Two novel porous luminescent metal-organic frameworks (MOFs, 1 and 2) have been constructed using 3,4-di(3,5-dicarboxyphenyl)phthalic acid using a hydrothermal method. Both MOFs can work as highly sensitive sensors to Fe(3+) by luminescent quenching. Analyses of the structures indicate a higher quenching efficiency of 2 because of the existence of active -COOH groups. Based on this consideration, the quenching mechanisms are studied and the processes are controlled by multiple mechanisms in which dynamic and static mechanisms of MOFs are discussed. Besides, the corresponding dynamic and static quenching constants are calculated, achieving the quantification evaluation of the quenching process. As expected, experimental data show that compound 2 possesses an overall quenching efficiency 6.9 times that of compound 1. Additionally, time-dependent intensity measurements, the shifts of the excitation spectrum and the appearance of a new emission peak all give visual proofs of the distinct mechanisms between the two MOFs.

[Effects of neregulin on rhesus monkey heart failure induced by rapid pacing].

OBJECTIVE: To investigate the effects of Recombined Human Neuregulin (NRG) on the expression of Glucose transporter (Glut1) in myocardium tissue of Rhesus Monkeys with Pacing-induced Heart Failure and the heart function. METHODS: Twenty four rhesus monkeys were randomly divided into three groups (shame operated group, heart failure group and NRG treated group), each with 8 monkeys. Heart failures were induced by rapid pacing (240 heart beats/min). Daily intravenous injection of recombined human NRG [3 microg/(kg x d)] and normal saline were given to the monkeys for 10 days for the NRG treated group and heart failure group respectively. Hemodynamic measurements including +dp/dt(max) and left ventricular systolic, end-diastolic blood pressures (LVSP and LVEDP) were conducted. The RT-PCR was applied to detect the expression level of PKB, Glut1 mRNA in the left ventricular cardiac muscle. RESULTS: The monkeys in the heart failure group had lower levels of + dp/dt(max) and LVSP and higher levels of LVEDP than those in the shame operated group (P < 0.05). The monkeys in the NRG treated group had higher levels of +dp/dt(max) than those in the heart failure group (P < 0.05). Lower expression of PKB, Glut1 mRNA in the heart failure group was observed compared with the shame operated group (P < 0.05) while the NRG treated group had a higher expression level of PKB,Glut1 mRNA by compared with the heart failure group (P < 0.05). CONCLUSION: Recombined human NRG can relieve heart failure syndroms through up-regulating the expression of PKB, Glut1 mRNA and improving energy supply of the ischemic cardiac muscle.