Latest ArticlesCarbon nanofibers (CNFs) have received extensive and in-depth studied as anodes for sodium-ion batteries (SIBs), and yet their initial Coulombic efficiency and rate capability remain enormous challenge at practical level. Herein, CNFs anchored with cobalt nanocluster (CNFs-Co) were prepared using chemical vapor deposition and thermal reduction methods. The as-prepared CNFs-Co shows a high initial Coulombic efficiency of 91% and a high specific discharge capacity of 246 mAh/g at 0.1 A/g after 200 cycles as anode for SIBs. Meanwhile, the CNFs-Co anode still delivers a high cycling stability with 108 mAh/g after 1000 cycles at 10 A/g. These excellent electrochemical properties could be attributed to the involved spin state Co, which endows CNFs with large interplanar spacing (0.39 nm) and abundant vacancy defects. Importantly, the spin state Co downshifts the p-band center of carbon and strengthens the Na+ adsorption energy from −2.33 eV to −2.64 eV based on density functional theory calculation. This novel strategy of modulating the carbon electronic structure by the spin state of magnetic metals provides a reference for the development of high-performance carbon-based anode materials.
The synthesis of degradable polymers with easy-to-break in-chain carbon-oxygen bonds has attracted much attention. This minireview introduces the synthesis of a variety of degradable polymers from the (co)polymerizations of several typical oxygenated monomers such as epoxides, cyclic carbonates, cyclic esters, carbon dioxide (CO2), carbonyl sulfide (COS), and cyclic anhydrides. We highlight the catalysts and mechanisms for these (co)polymerizations. The ring-opening copolymerization of five-membered carbonate with cyclic anhydride or COS has been introduced. We also highlight the synthesis of block copolymers and cyclic copolymers with well-defined sequences by the method of growing center switching. We hope that these new polymerization systems can provide new ideas for the development of degradable low-carbon polymers in the future.
Photocatalytic and photoinduced silyl radicals cascade cyclization procedures for the green and simple preparation of fused tetracyclic skeleton silylated indolo[2,1-a]isoquinoline-6(5H)-ones from 2-aryl-N-acryloyl indoles with hydrosilanes are developed. The photocatalytic reaction is carried out with 9,10-dicyanoanthracene (DCA) as an organophotocatalyst and 3-acetoxyquinuclidine as hydrogen atom transfer (HAT) catalyst at room temperature under metal- and oxidant-free conditions. The keys to the success of photoredox-catalytic conversion include (1) the reductive quenching of DCA* [E1/2(*P/P–) = +1.97 V vs. SCE in MeCN] by 3-acetoxyquinuclidine (Ep = +1.22 V vs. SCE in MeCN), and (2) the thermodynamic feasibility of hydrogen atom abstraction from hydridic Si–H bond by electrophilic N+•. Particularly, the simple photoinduced cascade cyclization using (TMS)3SiH with 2-aryl-N-acryloyl indoles was exploited via an electron−donor−acceptor (EDA) complex under visible light irradiation.
Metastable molybdenum carbide (α-MoC), as a catalyst and an excellent support for metal catalysts, has been widely used in thermo/electro-catalytic reactions. However, the selective synthesis of α-MoC remains a great challenge. Herein, a simple one-pot synthetic strategy for the selective preparation of metastable α-MoC is proposed by electrochemical co-reduction of CO2 and MoO3 in a low-temperature eutectic molten carbonate. The synthesized α-MoC shows a reed flower-like morphology. By controlling the electrolysis time and monitoring the phase and morphology of the obtained products, the growth process of α-MoC is revealed, where the carbon matrix is deposited first followed by the growth of α-MoC from the carbon matrix. Moreover, by analyzing the composition of the electrolytic products, the formation mechanism for α-MoC is proposed. In addition, through this one-pot synthetic strategy, S-doped α-MoC is successfully synthesized. Density functional theory (DFT) calculations reveal that S doping enhanced the HER performance of α-MoC by facilitating water absorption and dissociation and weakening the bond energy of Mo-H to accelerate H desorption. The present work not only highlights the valuable utilization of CO2 but also offers a new perspective on the design and controllable synthesis of metal carbides and their derivatives.
Hospital sewage contains various harmful pharmaceutical contaminants (e.g., antibiotics, anti-inflammatory agents, and painkillers) and pathogens (e.g., bacteria, viruses, and parasites), whose direct discharge into the environment will induce diseases and pose a powerful threat to human health and safety, and environmental ecology. In recent years, advanced oxidation processes (AOPs), particularly photocatalysis, electrocatalysis, and ozone catalysis have been developed as widespread and effective techniques for hospital sewage treatments. However, there is a lack of systematic comparison and review of the prior studies on hospital sewage treatment using AOPs systems. This review elaborates on the mechanisms, removal efficiencies, and advantages/disadvantages of these AOPs systems for hospital wastewater decontamination and disinfection. Meanwhile, some novel and potential technologies such as photo-electrocatalysis, electro-peroxone, Fenton/Fenton-like, and piezoelectric catalysis are also included and summarized. Moreover, we further summarize and compare the capacity of these AOPs to treat the actual hospital wastewater under the impact of the water matrix and pH, and estimate the economic cost of these technologies for practical application. Finally, the future development directions of AOPs for hospital wastewater decontamination and disinfection have been prospected. Overall, this study provides a comparison and overview of these AOP systems in an attempt to raise extensive concerns about hospital wastewater decontamination and disinfection technologies and guide researchers to discover the future directions of technologies optimization, which would be a crucial step forward in the field of hospital sewage treatment.
Implantable system maximizes drug concentration and continuously releases drugs near the tumor, which is an effective tool to solve the difficult retention of chemotherapy drugs in bladder cancer. In this work, a novel polysaccharide supramolecular injectable hydrogel (CCA hydrogels for short) is rapidly constructed by simply mixing cationic chitosan, anionic sulfobutyl ether β-cyclodextrin (SBE-β-CD) and a trace amount of silver ions. The injected hydrogel reconstituted and regained its shape in less than 1 h, and it can still maintain the elasticity suitable for the human body. By packaging the drug directly, the gel achieves a high concentration of doxorubicin, an anticancer drug. Using MB49-luc cells as the model of bladder tumor for anti-tumor in vivo, the CCA-DOX gel has obvious inhibitory effect on bladder tumor, and its inhibitory effect is much greater than that of free DOX. Therefore, this self-healing injectable hydrogel has great potential for in situ treatment of bladder cancer.
It is challenging to cooperatively improve the nonlinear optical (NLO) efficiency and the laser-induced damage threshold (LIDT). This work reports a novel IR NLO materials CsInP2S7 (CIPS) designed by combination the strategies of alkali metals substitution and microscopic NLO units PS4 introduction based on AgGaS2. CIPS was composed of strongly distorted [InS6]9- octahedra and [P2S7]4- dimers constructed by corner-sharing [PS4]3-, which increase the NLO efficiency and decrease thermal expansion anisotropy simultaneously. Compared with AgGaS2, CIPS exhibited strong phase matchable NLO response ca. 1.1 × AGS@2.1 µm, high LIDT ca. 20.8 × AgGaS2, and IR transparency up to 15.3 µm. Structural analysis and theoretical investigation confirmed that large SHG effect and ultrahigh LIDT of CIPS originated from the synergistic contribution of [InS6]9- octahedra and [P2S7]4- dimers. These results indicate that CIPS is a promising NLO candidate in the mid-IR region, and this study provides a new approach for developing potential NLO-LIDT compatible materials.
High monomer concentration is a requisite for engendering the aggregation-induced emssion (AIE) phenomenon as well as the formation of supramolecular polymers. Therefore, this is supposed to ensure the generation of AIE supramolecular polymers, wherein the monomer soluability takes effect. Nevertheless, parts of supramolecular monomers are considered as poessessing different soluability towards the same sovlent, through which the polymerzation process is thus hard to proceed. Interfacial polymerzation gets over the soluabilty restriction, providing a facile method for propelling the reaction of thesemonomers. Herein, we had prepared M1 containing tetraphenylethene (TPE) functionalized with two terpyridine derivatives, then making M1 dissolving in CHCl3 to give solutions. Cu2+ solutions were fabricated through dissolving CuCl2 into H2O. Towards mixing those solutions, AIE interfacial supramolecular polymers (AIEISPs) displaying green fluorescence were generated at the interface of two phases on the basis of metal-coordination between terpyridine and Cu2+. These AIEISPs were certificated to possess the stimuli-responsiveness, for which the excessive addition of tetrabutylammonium hydroxide would cause the structure destruction owing to the stronger bonding ability with Cu2+ than that of terpyridine. These fabricated AIEISPs had provided a new avenue to prepare AIE supramolecular polymers.
New pollutant pharmaceutical and personal care products (PPCPs), especially antiviral drugs, have received increasing attention not only due to their increase in usage after the outbreak of COVID-19 epidemics but also due to their adverse impacts on water ecological environment. Electro-Fenton technology is an effective method to remove PPCPs from water. Novel particle electrodes (MMT/rGO/Fe3O4) were synthesized by depositing Fe3O4 nanoparticles on reduced graphene oxide modified montmorillonite and acted as catalysts to promote oxidation performance in a three-dimensional electro-Fenton (3D-EF) system. The electrodes combined the catalytic property of Fe3O4, hydrophilicity of montmorillonite and electrical conductivity of graphene oxides, and applied for the degradation of Acyclovir (ACV) with high efficiency and ease of operation. At optimal condition, the degradation rate of ACV reached 100% within 120 min, and the applicable pH range could be 3 to 11 in the 3D-EF system. The stability and reusability of MMT/rGO/Fe3O4 particle electrodes were also studied, the removal rate of ACV remained at 92% after 10 cycles, which was just slightly lower than that of the first cycle. Potential degradation mechanisms were also proposed by methanol quenching tests and FT-ICR-MS.