Latest ArticlesPolycyclic aromatic hydrocarbons (PAHs) play an important role in the industry, and the development of new materials for the selective separation of PAHs is of great significance. In this work, we report a hexahedral metal-organic cage with low symmetry by subcomponent self-assembly. In this cage, the eight ZnⅡ centers adopt an interesting ΛΛ/ΔΔΔΔΔΔ or ΛΛΛΛΛΛ/ΔΔ configuration. This cage with a cavity volume of 520 Å3 can bind anthracene, phenanthrene, and pyrene to form 1:1 host-guest complexes, while the bigger triphenylene, chrysene, perylene, and coronene cannot be encapsulated. The binding constant Ka of pyrene is about 1.110 × 103 (mol/L)−1, which is more than an order of magnitude larger than that of anthracene and phenanthrene (111 (mol/L)−1, 277 (mol/L)−1, respectively). X-ray structure studies reveal that the pyrene is located in the cavity and stabilized by multiple CH⋅⋅⋅π interactions. After separation from a mixture of PAHs, pyrene with > 96.1% purity can be obtained. This work provides a useful method for the first time for the selective separation of pyrene from PAHs mixture by utilizing a metal-organic cage as the material, making it a useful tool for purifying and separating specific compounds from complex mixtures.
Methane chemistry is one of the "Holy Grails of catalysis". It is highly desirable but challenge to transform methane into value-added chemicals, because of its high C-H bonding energy (435 kJ/mol), lack of π bonding or unpaired electrons. Currently, commercial methane conversion is usually carried out in harsh conditions with enormous energy input. Photocatalytic partial oxidation of methane to liquid oxygenates (PPOMO) is a future-oriented technology towards realizing high efficiency and high selectivity under mild conditions. The selection of oxidant is crucial to the PPOMO performance. Hence, attentions are paid to the research progress of PPOMO with various oxidants (O2, H2O, H2O2 and other oxidants). Moreover, the activation of the selected oxidants is also highly emphasized. Meanwhile, we summarized the methane activation mechanisms focusing on the C-H bond that was broken mainly by •OH radical, O− specie or photogenerated hole (h+). Finally, the challenges and prospects in this subject are briefly discussed.
Polystyrene resins (PS) have been practical ion exchangers for radionuclides removal from water. However, nonspecific effects of ion exchange groups continue to be a major obstacle for emergency treatment with coexisting ions of high concentrations. The selectivity for Cs+ enables zirconium phosphate (ZrP) to be the most promising inorganic sorbent for radioactive cesium extraction, despite being difficult to synthesize and causing excessive pressure loss in fixed-bed reactors due to fine powder. Herein, through facile confined crystallization in host macropores, we prepared PS confined α-ZrP nanocrystalline (ZrP-PS). Size-screen sorption of layered α-ZrP and sulfonic acid group preconcentration of PS synergistically enable a considerably higher Cs+ affinity of ZrP-PS than PS, as confirmed by X-ray photoelectron spectroscopy (XPS) analysis. ZrP-PS demonstrated remarkable cesium sequestration performance in both batch and continuous experiments, with a high adsorption capacity of 269.58 mg/g, a rapid equilibrium within 80 min, and a continuous effluent volume of 2300 L/kg sorbents. Given the excellent selectivity for Cs+ and flexibility to separate from treated water, ZrP-PS holds great promise as purification packages for the emergency treatment of radioactively contaminated water.
NH3 in ambient air directly leads to an increase in the aerosol content in the air. These substances lead to the formation of haze to various environmental problems after atmospheric circulation and diffusion. Controlling NH3 emissions caused by ammonia escaping from mobile and industrial sources can effectively reduce the NH3 content in ambient air. Among the various NH3 removal methods, the selective catalytic oxygen method (NH3-SCO) is committed to oxidizing NH3 to environmentally harmless H2O and N2; therefore, it is the most valuable and ideal ammonia removal method. In this review, the characteristics of loaded and core-shell catalysts in NH3-SCO have been reviewed in the context of catalyst structure-activity relationships, and the H2O resistance and SO2 resistance of the catalysts are discussed in the context of practical application conditions. Then the effects of the valence state of the active center, oxygen species on the catalyst surface, dispersion of the active center and acidic sites on the catalyst performance are discussed comprehensively. Finally, the shortcomings of the existing catalysts are summarized and the catalyst development is discussed based on the existing studies.
Graphite tailings produced by natural graphite is usually regarded as garbage to be buried underground, which would result in a certain waste of resources. Here, in order to explore the utilization of natural graphite tailings (NGT), a liquid-polyacrylonitrile (LPAN) is used to modify the NGT fragments and aggregate them together to form secondary graphite particles with low surface area and high tap density. Moreover, the modified NGT show much better electrochemical performances than those of original one. When tested in full cells coupled with NMC532 cathode, the material achieves a high rate capability and cycle stability at the cutoff voltage of 4.25 V as well as 4.45 V, which maintains 84.32% capacity retention after 500 cycles at 1 C rate (4.25 V), higher than that of the pristine one (73.65%). The enhanced performances can be attributed to the use of LPAN to create a unique carbon layer upon graphite tailings to reconstruct surface and repair defects, and also to granulate an isotropic structure of secondary graphite particles, which can help to weaken the anisotropy of Li+ diffusion pathway and form a uniform, complete and stable solid-electrolyte-interface (SEI) on the surface of primary NGT fragments to promote a fast Li+ diffusion and suppress lithium metal dendrites upon charge and discharge.
Due to the limitations of conventional chemotherapy including side effects, poor prognosis, and drug resistance, there is an urgent need for the development of a novel multi-functional combined therapy strategy. Dopamine-modified oxaliplatin prodrug (OXA-DA) was successfully synthesized in this study to ameliorate the organ distribution of oxaliplatin for improving the drug efficacy and reducing toxic side effects, and OXA-DA was applied to develop a porous oxaliplatin cross-linked polydopamine nanoparticle for loading siPD-L1 to construct multifunctional nanoplatform. The multifunctional nanoplatform was modified with poly(2-ethyl-2-oxazoline) (PEOz), which occurred charge reversal in the tumor microenvironment, and exerted the lysosomal escape effect in tumor cells to improve the bioavailability of small interfering RNA targeting programmed cell death-ligand 1 (siPD-L1). The pH-responsive charge reversal, photothermal, biodegradation, lysosomal escape ability, PD-L1 protein degradation, toxicity properties and multiple antitumor effects were comprehensively evaluated in vitro and in vivo experiments. The findings indicated that OXA-DA-siPD-L1@PDA-PEOz excellently induced tumor cell necrosis and apoptosis as a result of the synergistic effect of chemo-photothermal therapy, and upregulated CD8+ T cells produced interferon-γ (IFN-γ) to further attack the tumor cells. In conclusion, the novel nanoplatform-mediated chemo/photothermal/immunotherapy has promising clinical applications in the treatment of malignant tumors.
Malignant tumors are the main diseases threatening human life. Using precise theranostics to diagnose and cure tumors has emerged as a new method to improve patient survival. Based on the current development of precise tumor imaging, image-guided tumor therapy has received widespread attention because it is beneficial for developing precise treatment of tumors, has the potential to improve the efficacy of tumor therapy and reduce the incidence of adverse side effects. Nanoprobes, which are nanomaterial functionalized with specific biomolecules, have intrigued intense interest due to their great potential in monitoring biorecognition and biodetection evens. Benefiting from the unique advantages of nanomaterials, including the easy surface functionalization, the unique imaging performances, and the high drug loading capacity, nanoprobes have become a powerful tool to simultaneously realize tumor precise imaging, diagnosis, and therapy. This review introduces the non-invasive tumor precise imaging and highlights the recent advances of image-guided oncotherapy mediated by nanoprobes in anti-tumor drug delivery, tumor precise surgical navigation, chemodynamic therapy, and phototherapy. Finally, a perspective on the challenge and future direction of nanoprobes in imaging-guided tumor theranostics is also discussed.
Aqueous zinc-ion batteries (AZIBs) have become a hotspot for electrochemical energy storage owing to the high safety, low cost, environmental friendliness, and favorable rate performance. However, the serious dissolution of cathode materials in aqueous electrolytes would lead to poor cyclability, which should be addressed before commercialization. Herein, we designed a Ti-doped V2O5 with yolk-shell microspherical structure for AZIBs. The Ti doping stabilizes the crystal structure and relieves the dissolution of V2O5 in aqueous ZnSO4 electrolyte. The optimized sample, Ti0.2V1.8O4.9, delivers a high capacity (355 mAh/g at 0.05 A/g) as well as good capacity retention (89% after 2500 cycles at 1.0 A/g). This work provides an effective strategy to mitigate the dissolution of cathode material in aqueous ZnSO4 electrolyte for cyclability enhancement.
A method for the generation of alkyl radicals from inert alkyl C-O bonds has been developed via an iron/borane reagent/alkoxide catalytic system, which can be employed for the synthesis of amines from nitroarenes with excellent efficiency. Preliminary mechanistic studies reveal that the amine synthesis may be involving a single electron transfer pathway to form alkyl radicals, and the low-valent iron species may be the active intermediates.
Lithium (Li)–CO2 battery is rising as an attractive energy-storage system with the competence of CO2 conversion/fixation. However, its practical development is seriously hindered by the high overpotential. Herein, a rational design on a highly catalytic Li–CO2 battery electrode built by graphdiyne powder as a multi-functional laminar scaffold with anchored highly dispersed Ru nanoparticles is explored. The strong interaction between the abundant acetylenic bond sites of graphdiyne scaffold and Ru nanoparticles can effectively promote the electrochemical progress and reduce the voltage polarization. The unique channels architecture of the cathodic catalyst with enough space not only accelerates CO2 diffusion and electrons/Li+ transport, but also allows a large amount of accommodation for discharged product (Li2CO3) to assure an advanced capacity. The corresponding Li–CO2 battery displays an advanced discharged capacity of 15,030 mAh/g at 500 mA/g, great capacity retention of 8873 mAh/g at 2 A/g, high coulombic efficiency of 97.6% at 500 mA/g and superior life span for 120 cycles with voltage gap of 1.67 V under a restricted capacity of 1000 mAh/g at 500 mA/g. Ex/in-situ studies prove that synergy between Ru nanoparticles and acetylene bonds of GDY can boost the round-trip CO2RR and CO2ER kinetics.