Latest ArticlesThe electro-Fenton process, with its capacity for in-situ H2O2 formation and Fe2+ regeneration, is a striking alternative to the traditional chemical-Fenton process. However, the frequent requirement of extra binders for electrode fabrication leads to low catalyst utilization, a complex fabrication process, and weak conductivity. Herein, a three-dimensional (3D) porous electrode was fabricated in-situ on a Ni foam (NF) substrate integrated with nitrogen-doped carbon nanotubes (N@C) derived from carbonization of zeolitic imidazolate framework-8 (ZIF-8) without any binder. The resulting 900/N@C-NF cathode (synthesized at 900 ℃) was high in surface area, N content, and degree of graphitization, achieved high performance of H2O2 production (2.58 mg L−1 h-1 H2O2/mg catalyst) at -0.7 V (vs. SCE), and enabled prompt regeneration of Fe2+. The electro-Fenton system equipped with the 900/N@C-NF cathode was effective in removing a diverse range of organic pollutants, including rhodamine B (RhB), phenol, bisphenol A (BPA), nitrobenzene (NB), and Cu-ethylenediaminetetraacetic acid (EDTA), and significantly attenuating the concentration of chemical oxygen demand (COD) in the real acid wastewater, exhibiting superior activity and stability. This binder-free and self-supporting electro-Fenton cathode was thus shown to be an attractive candidate for application to wastewater treatment, particularly those rich in organics, acids, and Fe3+/Fe2+.
The catalytic performance of light-derived CO2 reduction with H2O is strongly dependent on the separation efficiency of photogenerated carriers. Herein, the direct Z-scheme catalysts (g-C3N4/3DOM-WO3) of graphitic carbon nitride (g-C3N4) nanosheets decorated three-dimensional ordered macroporous WO3 (3DOM-WO3) were successfully fabricated by using the in-situ colloidal crystal template method. The slow light effect of 3DOM-WO3 photonic crystals expands the absorption of visible light and improves the utilization of light energy. The Z-scheme structure of g-C3N4/3DOM-WO3 catalysts is able to upgrade the separation efficiency of photogenerated electron-hole pairs. The g-C3N4/3DOM-WO3 photocatalyst, whose formation rate of CO product is 48.7 μmol g−1 h−1, exhibits the excellent catalytic activity for CO2 reduction. The transfer pathway of stimulated electrons over the g-C3N4/3DOM-WO3 photocatalyst is proposed and discussed. The present approach provides unique insights into the rational development of high-performance photochemical systems for efficient CO2 reduction into valuable carbon-containing chemicals and energy fuels.
A large surface area with high active site exposure is desired for the nano-scaled electrocatalysts fabrication. Herein, taking NiMoO4 nanorods for example, we demonstrated the advantages of the microwave-assisted hydrothermal synthesis method compared to the traditional hydrothermal approaches. Both monoclinic structured NiMoO4 in the nanorods morphology are found for these samples but it is more time-saving and efficient in the Ni-Mo synergism for the catalyst obtained by microwave-assisted hydrothermal syntheses method. When evaluated for urea oxidation, the current density can reach 130.79 mA/cm2 at 1.54 V, about 2.4 times higher than that of the counterpart catalyst (54.08 mA/cm2). Moreover, largely improved catalytic stability, catalytic kinetics and rapid charge transfer ability are found on the catalyst obtained by the microwave-assisted approach. The high catalytic performance can be attributed to the high surface area and active site exposure of NiMoO4 nanorods formed by microwave irradiation. Considering the less time, facile synthesis condition and efficient components synergism, the microwave-assisted hydrothermal synthesis method might work better for the nanostructure electrocatalysts fabrication.
We have prepared well-resolved Nbn+ (n = 1–10) clusters and report here an in-depth study on the essentially different reactivity with N2 and O2, by utilizing a multiple-ion laminar flow tube reactor in tandem with a customized triple quadrupole mass spectrometer (MIFT-TQMS). As results, the Nbn+ clusters are found to readily react with N2 and form adsorption products NbnN2m+; in contrast, the reactions with O2 give rise to NbnO1−4+Oproducts, and the odd-oxygen products indicate O-O bond dissociation, as well as increased mass abundance of NbO+ pertaining to oxygen-etching reactions. We illustrate how N2 prefers a physical adsorption on Nbn+ clusters with an end-on orientation for all the products, and allow for size-selective Nbn+ clusters to act as electron donor or acceptor in forming NbnN2m+. In contrast to these nitrides, the dioxides NbnO2+ display much larger binding energies, with O2 always as an electron acceptor, corresponding to superoxide or peroxide states in the initial reactions. Density-of-states and orbital analyses show that the interactions between Nbn+ and O2 are dominated by strong π-backdonation indicative of incidental electron transfer; whereas weak π-backdonation and simultaneous σ donation interactions exist in NbnN2+. Further, reaction dynamics analysis illustrates the different interactions for N2 and O2 in approaching the Nbn+ clusters, showing the energy diagrams for N2 adsorption and O-O bond dissociation in producing odd-oxygen products. Fragment analyses with orbital correlation and donor-acceptor charge transfer are also performed, giving rise to full insights into the reactivities and interactions of such transition metal clusters with typical diatomic molecules.
Thermally activated delayed fluorescent (TADF) materials capable of efficient solution-processed non-doped organic light-emitting diodes (OLEDs) are of important and practical significance for further development of OLEDs. In this work, a new electron-donating segment, 2,7-di(9H-carbazol-9-yl)-9,9-dimethyl-9,10-dihydroacridine (2Cz-DMAC), was designed to develop solution-processable non-doped TADF emitters. 2Cz-DMAC can not only simultaneously increase the solubility of compounds and suppress harmful aggregation-caused quenching, but also efficiently broaden the delocalization of the highest occupied molecular orbital and promote the reverse intersystem crossing process. Three new TADF emitters, 2-(2,7-di(9H-carbazol-9-yl)-9,9-dimethylacridin-10(9H)-yl)dibenzo[b, d]thiophene 5,5-dioxide (2Cz-DMAC-BTB), 2-(2,7-di(9H-carbazol-9-yl)-9,9-dimethylacridin-10(9H)-yl)-9H-thioxanthen-9-one (2Cz-DMAC-TXO), 2-(2,7-di(9H-carbazol-9-yl)-9,9-dimethylacridin-10(9H)-yl)thianthrene 5,5,10,10-tetraoxide (2Cz-DMAC-TTR), were developed by using 2Cz-DMAC segment as the electron-donor. As anticipated, the solution-processed non-doped OLEDs employing 2Cz-DMAC-BTB, 2Cz-DMAC-TXO and 2Cz-DMAC-TTR as the emitters respectively exhibited green, orange and red emissions with maximum external quantum efficiencies of 14.0%, 6.6% and 2.9%. These results successfully demonstrate the feasibility and convenience of developing efficient solution-processable non-doped TADF emitters based on 2Cz-DMAC segment.
The self-assembly characteristics of tetrathiafulvalene (TTF) derivatives molecules 1–3 at the 1-phenyloctane/HOPG (HOPG = highly oriented pyrolytic graphite) interface had been carefully studied by scanning tunneling microscopy (STM) method. The number of F atoms on the phenyl group had significantly affected the self-assembly structures. High-resolution STM images make clear the different assembly structures between the molecules 1–3, which attribute to the different F atom numbers and pyridine group in the molecule. Density functional theory (DFT) calculations have been performed to reveal the formation mechanism.
Biological drugs are attracting tremendous attention in disease treatment. However, their application is significantly limited by their inherent properties, such as high hydrophilicity, poor membrane-permeability, low stability, and larger size. Liposome-based drug delivery systems are emerging as promising tools to improve their delivery, owing to their ability to reduce toxicity, improve bioavailability, and enhance the therapeutic efficacy of the drug by optimizing delivery to the specific target site. Here, we reviewed the types of liposomes and their applications as carriers for biological drugs to treat various diseases, emphasized the commercial products, and ultimately provided perspectives in this field.
In the field of advanced oxidation processes (AOPs) of wastewater, many materials can be used as heterogeneous catalysts. The role of these catalysts is to activate oxidants and generate reactive oxygen species (ROS) to decompose refractory pollutants. Perovskite oxide, an emerging catalyst in the field of AOPs, has been extensively studied in wastewater treatment. Nevertheless, the application of perovskite in AOP systems still faces some problems, such as leaching of metal ions, a small surface area, a low number of active sites, etc. Herein, this critical review comparatively examines the activation mechanisms of peroxymonosulfate, hydrogen peroxide, and peroxydisulfate. Furthermore, the formation pathways of oxidizing species based on recent advances in experimental and theoretical studies were evaluated. In addition, the impacts of water parameters and constituents such as initial pH, oxidant concentration, catalyst dosage, natural organic matter, halide, phosphate, and carbonate were discussed. Finally, a critical discussion and prospects of mechanism exploration and possible materials development are proposed to confront the existing challenges in the application of perovskite oxides in AOPs.
Chemiluminescence immunoassay (CLIA) has always been a great challenge in detecting cardiac troponin I (cTnI) in whole blood samples without centrifugation because of the interference of red blood cells and low sensitivity. In this study, the antigens and erythrocytes in the blood were captured by the antibodies immobilized on the magnetic particles, recognized by another biotin-conjugated cTnI antibody and detected by streptavidin/acridine aster-conjugated polychloromethylstyrene microspheres (PCMS). After magnetic separation, the supernatant was transferred and measured. No significant difference was noted between the cTnI concentrations of the serum samples, plasma samples and whole blood. The prepared PCMS provided more functional areas to conjugate streptavidin and acridinium ester, so the immunoassay has highly sensitive, the limits of blank at 0.012 ng/mL, and functional sensitivity at 0.019 ng/mL with a CV of 20%, and 0.058 ng/mL with a CV of 10%. Total precision of any sample type ranged from 2.62%~5.67%. The assay was linear over the studied range of 0.01-50.00 ng/mL, and no hook effect was found when cTnI concentrations reached 1900 ng/mL. No significant interference was noted with the potential endogenous interfering substances. Compared with the commercial kit (Abbott assay kit), the correlation coefficient was 0.9859. A washing-free CLIA was established for the rapid detection of cTnI in human whole blood, using erythrocyte capture antibodies-conjugated magnetic nanoparticles for eliminating the influence of erythrocytes and PCMS for signal amplification, which showed great potential in clinical application.
Carbon dots (CDs), novel luminescent zero-dimensional carbon nanomaterials, have been widely applied due to their low toxicity, optimal optical properties, and easy modification. However, the current controllable equipment and mechanism explanation of CDs are relatively vague and require urgent resolution. Full-color emission CDs, an essential CDs category, have attracted people's attention given their light and color-tunable properties. In addition to a wider range of biological and optoelectronic device applications, full-color emission CDs have similar structures and significantly affected the fluorescence mechanism of CDs. At present, few studies have reported on the summary research of CDs emitted by its full color, which greatly limits the development of CDs mechanisms and applications. As such, the present review detailed the full-color CDs development status, to which a suitable method for preparing full-color CDs was presented and the existing fluorescence emission mechanism of full-color CDs was summarized. Herein, we comprehensively introduced full-color CDs applications in biology and optoelectronics. Finally, we made an outlook on the development and potential applications of full-color CDs. The present review aims to contribute novel insights and methods for understanding full-color CDs.