Latest ArticlesBiomass-derived porous carbon with developed pore structure is critical to achieving high performance electrode materials. In this work, we report a grape-based honeycomb-like porous carbon (GHPC) prepared by KOH activation and carbonization, followed by N-doping (NGHPC). The obtained NGHPC exhibits a unique honeycomb-like structure with hierarchically interconnected micro/mesopores, and high specific surface area of 1268 m2/g. As a supercapacitor electrode, the NGPHC electrode exhibits a remarkable specific capacitance of 275 F/g at 0.5 A/g in a three-electrode cell. Moreover, the NGHPC//NGHPC symmetric supercapacitor displays a high energy density of 12.6 Wh/kg, and excellent cycling stability of approximately 95.2% capacitance retention after 5000 cycles at 5 A/g. The excellent electrochemical performance of NGHPC is ascribed to its high specific surface area, honeycomb-like structure and high-content of pyrodinic-N (36.29%). It is believed that grape-based carbon materials show great potential as advanced electrode materials for supercapacitors.
Recently, increasing attention has been paid on extending the π-conjugation structures of viologens (1, 1'-disubstituted-4, 4'-bipyridylium salts) by incorporating planar aromatic units into the bipyridinium backbones. Various viologen derivatives with extended π-conjugation structures have been synthesized, including the N-termini aromatic substituted viologens, the extended π-conjugated viologens (denoted as ECVs) as well as the π-conjugated oligomeric viologens (denoted as COVs). These compounds typically exhibit interesting properties distinguished from those of an isolated viologen unit, which make them as new class of electron deficient supra-/molecular building blocks in supramolecular chemistry and materials science. In this review, we would like to highlight the recent advances of viologen derivatives with extended π-conjugation structures in versatile applications ranging from electrochromic and energy storage materials, the ECV/COV-based supramolecular self-assembly systems including the linear supramolecular polymers and 2D/3D supramolecular organic frameworks (SOFs), to the viologen-based covalent organic frameworks (COFs)/networks. We hope this review will serve as an in-time summary worthy of referring, more importantly, to provide inspiration in the rational design of novel molecules with unexplored properties and functions.
Formaldehyde (HCHO) is one kind of common indoor toxic pollutant, the catalytic oxidation degradation of formaldehyde at room temperature is desired. In this work, a new single atomic catalyst (SAC), Al doped graphene, for the catalytic oxidation of HCHO molecules was proposed through density function theory (DFT) calculations. It is found that Al atoms can be adsorbed on graphene stably without aggression. Then HCHO can be effectively oxidized into CO2 and H2O in the presence of O2 molecules on Al doped graphene with a low energy barrier of 0.82 eV and releasing energy of 2.29 eV with the pathway of HCHO → HCOOH → CO → CO2. The oxidation reaction can happen promptly with reaction time τ = 56.9 s at the speed control step at room temperature. Therefore, this work proposed a high-performance catalyst Al-doped graphene without any noble metal for HCHO oxidation at ambient temperature, and corresponding oxidation pathway and mechanism are also deeply understood.
By using ambient air as the oxidant and malic acid as the promoter, a practical method for the preparation of 2-aminobenzothiazoles through visible-light-initiated cascade reaction of aromatic amines and KSCN in eco-friendly bis(methoxypropy)ether under metal-, hazardous additive-, photocatalyst-free conditions was established.
Manganese-catalyzed hydrogenation of unsaturated molecules has made tremendous progresses recently benefiting from non-innocent pincer or bidentate ligands for manganese. Herein, we describe the hydrogenation of quinolines and imines catalyzed by simple manganese carbonyls, Mn2(CO)10 or MnBr(CO)5, thus eliminating the prerequisite pincer-type or bidentate ligands.
Rh/ZhaoPhos-catalyzed asymmetric hydrogenation of a series of (E)-2-(chroman-4-ylidene)acetates was successfully developed to prepare various chiral 4-substituted chromanes with high yields and excellent enantioselectivities (up to 99% yield, 98% ee). Moreover, the gram-scale hydrogenation could be performed well in the presence of 0.02 mol% catalyst loading (TON = 5000), the hydrogenation product was easily converted to access other important compounds, which demonstrated the synthetic utility of this asymmetric catalytic methodology.
A synthetic study toward the structurally complex rearranged-type C19-diterpenoid alkaloids leading to construction of the strained 6/3/5/6 tetracyclic core is presented. The synthesis features an intramolecular Diels-Alder cycloaddition reaction to assemble the highly substituted central cyclopropane motif, which may serve as a key strategy for the total synthesis of relevant natural product molecules.
To achieve high power conversion efficiency (PCE), three porphyrin sensitizers have been synthesized and explored to simultaneously enhance the photocurrent (Jsc) and photovoltage (Voc). On basis of the XW4, a benzothiadiazole (BTD) unit has been introduced to afford XW57 with the aim to extend the absorption wavelength and enhance the light harvesting ability. As a result, a Jsc of 13.72 mA/cm2 has been obtained for XW57, higher than that of XW4. On this basis, XW58 has been prepared by modifying the carbazole-based donor with two bulky dihexyloxyphenyl groups, and the superior anti-aggregation character raises the Voc from 781 mV (XW4) to 844 mV. When both the BTD unit and the bulky groups are introduced to the acceptor and donor units, respectively, the resulting sensitizer XW59 exhibits a highest PCE value of 7.34% with synergistically enhanced Jsc of 13.19 mA/cm2 and Voc of 793 mV. These results provide further insight into developing high performance dye-sensitized solar cells
Last two decades, with the rapid changes and development of nanotechnology and biological materials, diverse multi-functional nanomaterials emerging, which offers a novel way to treat and diagnose diseases, and therefore spawned the new biomedical technology of theranostics, which integrates the treatment and diagnosis or monitoring of diseases into one. Ag2S as a bio-nanomaterial with low biotoxicity has attracted more and more attention due to its good photoluminescence properties and fluorescence imaging of small animals in the second near-infrared region (NIR-II). Meanwhile, Ag2S has the ability to absorb near-infrared light strongly because of its local surface plasma resonance (LSPR) effect and had become a kind of photothermal converters with good photothermal conversion efficiency. More interestingly, both photothermal effect and fluorescence characteristics of Ag2S nanoparticles (NPs) are closely related to their particle sizes. However, the relationship between photothermal effect and fluorescence characteristics of Ag2S NPs and their sizes has not been reviewed so far. Herein, the synthesis methods and influencing factors of synthesize Ag2S NPs with different sizes were compared firstly, and then the photothermal effect and fluorescence characteristics of Ag2S NPs with different sizes were summarized. Finally, the possibilities and challenges of using Ag2S NPs to construct theranostic agent were discussed in the end.
Sulfate radical anion (SO4·-) based Fenton-like reaction have recently received a large quantity of attention owing to their strong oxidative capacity and high selectivity toward organic pollutants. However, the development of a high-efficient catalyst for activation of peroxymonosulfate (PMS) with a fast separation is still challengeable. Herein, magnetic mesoporous silica composites with a yolk-shell structure (Fe@void@mSiO2) have been prepared via a successive coating strategy, followed by a hightemperature in-situ treatment and demonstrated as a high-efficient and fast magnetic separable catalyst for the activation of PMS. The resultant material possesses a well-defined yolk-shell structure with high specific surface area (~495.0 m2/g), uniform pore size (~6.9 nm) and super large magnetic susceptibility (~105 emu/g). Owing to the unique properties, the material possesses an excellent degradation activity for tetracyclines (TC), which is much higher than the commercialized Zero Valent Iron (ZVI) nanoparticles. Additionally, the catalyst is able to work over a broad pH range and be quickly recycled by using an external magnetic field. This research provides a promising strategy for the synthesis and design of multifunctional catalyst for the Fenton-like process.
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