Latest Articlesg-C3N4 have been widely used in the fields of photocatalytic hydrogen production, photocatalytic degradation of dyes and oxidative degradation of toxic gases due to their excellent performance. It has attracted extensive attention in recent years due to its highly efficient photocatalytic capacity of hydrogen generation, water oxidation, carbon dioxide reduction and degradation of organic pollutants. Because of the abundant carbon and nitrogen composition of the earth, large-scale production and industrial applications of this material are possible. The modification of this material makes its performance more excellent so that this new material can obtain a steady stream of vitality. These outstanding works have become important materials and milestones on the road to mankind's photocatalytic hydrogen production. This review will begin with the basic idea of designing, synthesizing and improving g-C3N4 based photocatalytic materials, and introduce the latest development of g-C3N4 photocatalysts in hydrogen production from four aspects of controlling the carbon/nitrogen ratio, morphology, element doping and heterojunction structure of g-C3N4 materials.
Rheumatoid arthritis (RA), as a chronic autoimmune disease, damages the bone and cartilage of patients, and even leads to disability. Therefore, the diagnosis and treatment of RA is particularly important. However, due to the complexity of RA, it is difficult to make effective early diagnosis of RA, which is detrimental to RA treatment. Besides, long-term intake of anti-RA drugs can also cause damage to patients' organs. The emergence of nanotechnology provides the new train of thoughts for the diagnosis and treatment of RA. And the combination of diagnosis and therapy is an ideal method to solve the problem of disease management of RA patients. In this review, we summarize the mechanism and microenvironment of RA, discuss the commonly used diagnostic techniques and therapeutic drugs for RA, and review their advantages and disadvantages. New nanotherapy strategies such as drug-carrying nanoparticles, PTT, PDT are listed, and their applications in RA treatment are also summarized. In addition, multimodal imaging, combined therapy and responsive diagnosis and treatment are also summarized as important contents. At last, we also review typical nanocarriers that can be used in the integration of diagnosis and therapy, and discussed their potential applications in RA theranostics.
Sulfonium salts and sulfur ylides are important S(Ⅳ) motifs, and have displayed many unique reactivities to provide simple, effective, and often stereoselective synthesis toward sulfur containing compounds. Impressive developments have been witnessed within this field during the past several years. In light of the increasing demand of organosulfur compounds across the range of chemical sciences, our aim of this review is to provide a concise overview of recent advances of sulfonium salt and sulfur ylide chemistry. Selected examples are organized in three parts on the basis of their role in organic reactions (reactants, intermediates and catalysts).
Single atom catalysts (SACs) with isolated metal atoms dispersed on supports exhibit distinctive performances for electrocatalysis reactions. The designable realization of well-dispersed single metal atoms is still a great challenge owing to their ease of aggregation. Here, Mo single atomic sites (Mo-N3C) combined with some ultrasmall Mo2C/MoN clusters (Mo-SA/Mo2C-MoN-Cs, mean diameter < 2 nm) on nitrogen-doped porous carbon were synthesized via a simple pyrolysis of bimetallic Zn/Mo metal-organic frameworks. X-ray absorption near edge spectra (XANES) in combination with various characterizations show that most of Mo species in sample exist in the form of single sites and the exact structure is Mo-N3C. Density functional theory (DFT) calculation further shows that as the number of N-coordination in the Mo-NxC moieties increases, the positive charge of Mo atoms increases. The single Mo atoms in Mo-N3C have the best capability of N2 adsorption, which may serve as main active sites for further electrochemical N2 reduction.
A wide variety of molecular probes have been developed for real-time analysis, but most of organic fluorophores possess small Stokes shifts and self-absorption or inner filter effect that could not be avoided. In this study, a new dicyanoisophorone-based derivative (E)-O-(4-(2-(3-(dicyanomethylene)-5, 5-dimethylcyclohex-1-en-1-yl)vinyl)phenyl)diphenylphosphinothioate (λex = 405 nm, λem = 551 nm, denoted as ICM-S) with strong push-pull electron effect has been afforded and it exhibits red shift for absorption from 407 nm to 426 nm with distinct color change from pale yellow to deep yellow upon exposure to Hg2+. Moreover, an easily distinguishable fluorescence color change follows the route from green, yellow to red in the presence of Hg2+ over the range of 0-90 μmol/L (detection limit = 137 nmol/L) can be observed by the naked eye under a UV lamp irradiation. Chlorodiphenylphosphine and sublimed-sulfur are incorporated as responsive sites and P-O bond has been cleaved upon the addition of mercury ions. During the recognition process, such dicyanoisophorone dye (ICM-S) has been evolved to 2-(3-(4-hydroxystyryl)-5, 5-dimethylcyclohex-2-enylidene) malononitrile (ICM OH). Clear evidences in the chemical processes can be identified via single crystal X-ray diffraction, spectroscopic analysis, photophysical studies and titration experiments. With the aim of exploring its potential in biological systems, its in vitro responses to Hg2+ have been evaluated in 293 Tcells and the effectiveness in zebrafish model has also been verified.
The strategy of adopting cheap precursors or abundant resources, which can be obtained directly from nature, is a simple and excellent method of introducing accessible research into environmentally friendly development. Moreover, this is also an urgent requirement for the sustainable development of green technology. Herein, we introduce a simplistic and expandable method to prepare metal-free biomass-derived nitrogen self-doped porous activation carbon (N-PAC) with large specific surface area (SBET = 1300.58 m2/g). Moreover, the manufactural electrocatalysts exhibit prominent oxygen reduction reaction (ORR) performance in all PH values. As compared with the commercial Pt/C catalyst, the N-PAC/800 with a positive onset potential at 10 mA/cm2 (0.93 V), half-wave potential (0.87 V), and limiting current (6.34 mA/cm2) bring to light excellent catalytic stability, selectivity, and much-enhanced methanol tolerance. Furthermore, the prepared electrocatalysts possess considerable hydrogen evolution reaction (HER) performance with a less onset potential of 0.218 V (acidic medium) and 0.271 V (alkaline medium) respectively, which can show similar catalytic activity across the whole pH range. Such bifunctional electrocatalyst, with excellent electrocatalytic properties, resource-rich, low cost, and environmental-friendly, hold a promising application in energy conversion and reserve.
Hollow nanostructures have attracted increasing research interest in hydrogen evolution reaction owing to their unique structural features. Herein, Ni–Co mixed metal phosphide hollow and porous polyhedrons was successfully composited (expressed as NiCoP). Benefiting from the synergistic effects of ZIF-67 by doping Ni elements and the well-defined hollow and porous structure, the as-synthesized NiCoP hollow and porous polyhedrons exhibit better electrochemical properties and mechanical stability for hydrogen evolution reaction over a pH-universal range, with a small Tafel slopes of 72, 101, 176 mV/dec, and a low overpotential of 82, 102, 261 mV at a current density of 10 mA/cm2 in 0.5 mol/L H2SO4, 1 mol/L KOH and 1 mol/L phosphate buffer solution (PBS). This general strategy can also be applied to fabricate other hollow cobalt-based phosphides and MOFs-derived materials for HER.
Traditional matrix does not allow matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) to analyze volatile compounds, because volatile analytes may vaporize during the sample preparation process or in the high vacuum circumstance of ion source. Herein, we reported a Co and N doped porous carbon material (Co-NC) which were synthesized by pyrolysis of a Schiff base coordination compound. Co-NC could simultaneously act as adsorbent of volatile compounds and as matrix of MALDI MS, to provide the capability of MALDI MS to analyze volatile compounds. As adsorbent, Co-NC could strongly adsorb and enrich the volatile compounds in perfume and herbs, and hold them even in the high vacuum circumstance. On the other hand, Co-NC could absorb the energy of the laser, and then transfer the energy to the analyte for desorption and ionization of analyte in both negative and positive ionization modes. Additionally, the background interferences were avoided in the low-mass region (< 500 Da) when using Co-NC as matrix, overcoming the challenges of MALDI MS analysis of small molecule compounds. In summary, Co-NC as matrix tremendously extended the application of MALDI MS.
All-solid-state Li metal battery has been regarded as a promising battery technology due to its high energy density based on the high capacity of lithium metal anode and high safety based on the all solid state electrolyte without inflammable solvent. However, challenges still exist mainly in the poor contact and unstable interface between electrolyte and electrodes. Herein, we demonstrate an asymmetric design of the composite polymer electrolyte with two different layers to overcome the interface issues at both the cathode and the anode side simultaneously. At the cathode side, the polypropylene carbonate layer has enough viscosity and flexibility to reduce the inter-facial resistance, while at the Li anode side, the polyethylene oxide layer modified with hexagonal boron nitride has high mechanical strength to suppress the Li dendrite growth. Owing to the synergetic effect between different components, the as-prepared double layer composite polymer electrolyte demonstrates a large electrochemical window of 5.17 V, a high ionic conductivity of 6.1×10-4 S/cm, and a transference number of 0.56, featuring excellent ion transport kinetics and good chemical stability. All-solid-state Li metal battery assembled with LiFePO4 cathode and Li anode delivers a high capacity of 150.9 mAh/g at 25 ℃ and 0.1 C-rate, showing great potential for practical applications.
The cascade reactions of alkyl α-diazoesters and ynones using Al(OTf)3 as the catalyst are described. A series of 4-substituted pyrazoles were obtained via [3 + 2] cycloaddition, 1, 5-ester shift, 1, 3-H shift, and N—H insertion process. Deuterium labelling experiments, kinetic studies and control experiments were carried out for the rationalization of the mechanism.
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