Large‐capacity energy storage devices are attracting widespread research attention. However, the decreased capacity of these devices due to cold weather is a huge obstacle for their practical use. In ...this study, an electrochemical self‐adaptive reconstructed CuxS/Cu(OH)2‐based symmetric energy storage device is proposed. This device provides a satisfactorily enhanced photothermal capacity under solar irradiation. After electrochemical reconstruction treatment, the morphological structure is rearranged and the CuxS component is partially converted to electrochemically active Cu(OH)2 with the introduction of a large number of active sites. The resulting CuxS/Cu(OH)2 electrode provides a significant capacitance of 115.2 F cm−2 at 5 mA cm−2. More importantly, its wide working potential range and superior photo‐to‐thermal conversion ability endow CuxS/Cu(OH)2 with superb performance as full‐purpose photothermally enhanced capacitance electrodes. Under solar irradiation, the surface temperature of CuxS/Cu(OH)2 is elevated by 76.6 °C in only 30 s, and the capacitance is boosted to 230.4% of the original capacitance at a low temperature. Furthermore, the assembled symmetric energy storage device also delivers a photothermal capacitance enhancement of 200.3% under 15 min solar irradiation.
The electrochemical reconstructed CuxS/Cu(OH)2 with high capacitive performance (115.2 F cm−2) delivered a superior photothermal conversion with 76.6 °C in only 30 s. The excellent photothermal effect of CuxS/Cu(OH)2 electrodes enhances the capacitance by 200.3% after solar irradiation for 15 min in a sub‐freezing environment.
In this work, we use a double‐layered stack of TiO2 nanotubes (TiNTs) to construct a visible‐light‐triggered drug delivery system. The key for visible light drug release is a hydrophobic cap on the ...nanotubes containing Au nanoparticles (AuNPs). The AuNPs allow for a photocatalytic scission of the hydrophobic chain under visible light. To demonstrate this principle, we loaded ampicillin (AMP) into the lower part of the TiO2 nanotube stack, triggered visible‐light‐induced release, and carried out antibacterial studies. The release from the platform becomes most controllable if the drug is silane‐grafted in the hydrophilic bottom layer for drug storage. Thus, visible light photocatalysis can also determine the release kinetics of the active drug from the nanotube wall.
A visible‐light‐triggered drug delivery system is constructed based on a double‐layered stack of TiO2 nanotubes. The key for visible light drug release is a hydrophobic cap on the nanotubes containing Au nanoparticles, where SPR with the TiO2 conduction band provides the active species for chain scission. The system was tested in antibacterial experiments against E. coli.
Potassium ion batteries (KIBs) have emerged as a promising energy storage system, but the stability and high rate capability of their electrode materials, particularly carbon as the most investigated ...anode ones, become a primary challenge. Here, it is identified that pitch‐derived soft carbon, a nongraphitic carbonaceous species which is paid less attention in the battery field, holds special advantage in KIB anodes. The structural flexibility of soft carbon makes it convenient to tune its crystallization degree, thereby modulating the storage behavior of large‐sized K+ in the turbostratic carbon lattices to satisfy the need in structural resilience, low‐voltage feature, and high transportation kinetics. It is confirmed that a simple thermal control can produce structurally optimized soft carbon that has much better battery performance than its widely reported carbon counterparts such as graphite and hard carbon. The findings highlight the potential of soft carbon as an interesting category suitable for high‐performance KIB electrode and provide insights for understanding the complicated K+ storage mechanisms in KIBs.
The cycling stability of anode materials in potassium‐ion batteries (KIBs) is challenged by the large size of K+ itself. The findings not only demonstrate the promising potential of soft carbon as a category suitable for high‐performance KIB electrodes, but also provide insights into the complicated K+ storage mechanisms in carbon anodes of KIBs.
Chiral differentiation is an important topic in diverse fields ranging from pharmaceutics to chiral synthesis. The improvement of sensitivity and the elucidation of the mechanism of chiral ...recognition are still the two main challenges. Herein, a plasmon-free semiconductive surface-enhanced Raman spectroscopy (SERS) substrate with sensitive chiral recognition ability is proposed for the discrimination of enantiomers. A homochiral environment is constructed by typical π-π stacking between
l
-tryptophan (
l
-Trp) and phenyl rings on well-aligned TiO
2
nanotubes (TiO
2
NTs). Using 3,4-dihydroxyphenylalanine (DOPA) enantiomers as the targets and the chelating interaction of Fe
3+
-DOPA for the onsite growth of Prussian blue (PB), the enantioselectivity difference between
l
-DOPA and
d
-DOPA on the homochiral substrate can be directly monitored from PB signals in the Raman-silent region. By combining the experimental results with molecular dynamic (MD) simulations, it is found that satisfactory enantioselective identification not only requires a homochiral surface but also largely depends on the chiral center environment-differentiated hydrogen-bond formation availability.
An intelligent enantioselective identification strategy is designed to demonstrate that both enantioselectivity and stereoselectivity are crucial factors for chiral sensing.
Maintaining the high activity of an enzyme is a fundamental requirement to widen the application of metal–organic frameworks (MOFs) in the biotechnology, biosensor, and biomedicine fields. However, ...it is still challenging to monitor and understand an MOF environment-related activity for an enzyme. Here, we developed a MOFs-in-nanochannels configuration for broadening the biocatalytic activity of an enzyme in MOFs on demand. ZIF-8 Zn(mim)2, Hmim = 2-methylimidazolated grown in TiO2 nanochannels is used as the platform, and cytochrome C (CytC) is used as a model enzyme encapsulated in ZIF-8. The enzymatic catalytic process converts 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) to a positively charged product (ABTS+). On the basis of current–voltage properties, the change of ion transport characteristics in nanochannels can be monitored with time. The ZIF-8 encapsulating CytC molecules not only exhibit a significantly enhanced enzymatic activity in a wide temperature region (37–80 °C) but also have remarkably long storage stability at room temperature. The results of quantum mechanical calculation indicate that the Fe–S bond of CytC is inclined to break in the environment of ZIF-8 owing to the confinement effect of the MOF structure, favorable for enzymatic catalysis. The MOFs-in-nanochannel configuration provides an innovative and label-free design for the onsite monitoring of catalytic activity of an enzyme in MOFs, which holds great potential in constructing biosensing platforms with remarkable performance and stability.
The low penetration depth of UV light in mammalian tissue is the critical limitation for the use of TiO2-based photocatalysis in biomedical applications. In this work, we develop an effective ...near-infrared (NIR)-active photocatalytic platform that consists of a shell structure of upconversion nanocrystals decorated on a core of Au/dark-TiO2. The heart of this system is the strong photocatalytic activity in the visible region enabled by the gold surface-plasmon resonance on dark TiO2 (D-TiO2). Simulation and experiment demonstrate for an optimized Au/D-TiO2 combination a highly enhanced light absorption in the visible range. Using ampicillin sodium (AMP) as model drug, we exemplify the effective use of this principle by demonstrating a NIR light-triggered photocatalytic payload release. Importantly, the photocatalytically generated reactive oxygen species can effectively inactivate AMP-resistant bacteria strains, thus maintaining an antibacterial effect even after all drug is released. Overall, we anticipate that the here-introduced NIR-light-active photocatalytic cascade can considerably widen TiO2-based photocatalysis and its applications into the infrared range.
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•Chiral AIE compounds are recently developed very rapidly.•Chiral AIEgens display excellent chiral recognition, ee analysis and CPL properties.•Review paper about preparation of ...chiral AIEgens and their applications is scarce.
Due to immense potential in using as chemo/biosensors and solid emitters, aggregation-induced emission (AIE) phenomenon is attracting huge interest in scientific community. After endowed with chirality, the resultant chiral AIE luminogens (AIEgen), just like a tiger with added wings, can display more and stronger promising functionalities. Moreover, many classic luminophores can be transformed into AIEgens from notorious aggregation-caused quenching (ACQ) compounds as soon as they are attached with chiral groups. Compared with other chiral fluorescent receptors and chiral emitter, chiral AIEgens have displayed unique and outstanding advantages. Firstly, chiral AIEgen can differentiate two enantiomers of chiral analyte by 1.68 × 104 fold difference and get a chiral magnification up to 2.5 × 103 times due to aggregation. In addition, two enantiomers of up to 18 chiral carboxylic acids can be recognized just by using only one chiral AIEgen receptor and enantiomeric excess (ee) of chiral analytes at uM level can be measured. Furthermore, accurate ee analysis was carried out for the first time from fluorescence wavelength change rather than intensity change of the chiral AIEgen receptor. Therefore, the chiral AIEgens show unprecedentedly high selectivity, high sensitivity, high applicability, and high accuracy. Secondly, in the area of organic circularly polarized luminescence (CPL) materials, the CPL dissymmetry factor (glum) of chiral AIEgen can get to 1.42 that is near to the theoretical value of 2, making a breakthrough progress while the |glum| of previous organic luminophores is generally between 10−5 and 10−2. Furthermore, the highly efficient circularly polarized organic light-emitting diodes (CPOLEDs) are constructed for the first time by chiral AIEgens. Thirdly, chiral AIEgens enable novel display technology under different lighting conditions to be possible. More importantly, due to AIE effect, AIEgens are very beneficial for disclosing the mechanism of chiral transfer and magnification between molecules, which is thought to be the key for evolution of homochirality in natural world and preparation of chiral materials with hierarchical structures. For the above reason, chiral AIEgens have been brought to extensive attention and a large number of research works about them are reported. To take an overall view on chiral AIEgens and facilitate the development of chiral AIEgens, it is necessary to make a full review on the chiral AIEgens. This review covers the following contents: (1) construction of chiral AIEgens including propeller-like chiral AIEgens, chiral AIEgens with optically pure groups, polymer chiral AIEgens and supramolecular chiral AIEgen system; (2) chiral recognition and ee determination of chiral carboxylic acids, chiral amines, α-amino acids, and chiral neutral molecules by chiral AIEgens; (3) performance of chiral AIEgens in circular dichroism (CD), CPL and CPOLEDs; (4) other versatile application researches related to chiral AIEgens.
Monosaccharides play significant roles in daily metabolism in living organisms. Although various devices have been constructed for monosaccharide identification, most rely on the specificity of the ...natural enzyme. Herein, inspired by natural ionic channels, an asymmetrical MOF-in-nanochannel architecture is developed to discriminate monosaccharide enantiomers based on cascade reactions by combining oxidase-mimicking and Fenton-like catalysis in homochiral mesoporous CuMOF pockets. The identification performance is remarkably enhanced by the increased oxidase-mimicking activity of Au nanoparticles under a local surface plasmon resonance (LSPR) excitation. The apparent steady-state kinetic parameters and nano-fluidic simulation indicate that the different affinities induced by Au-LSPR excitation and the confinement effect from MOF pockets precipitate the high chiral sensitivity. This study offers a promising strategy for designing an enantiomer discrimination device and helps to gain insight into the origin of stereoselectivity in a natural enzyme.
An asymmetrical architecture is developed to discriminate monosaccharide enantiomers based on enzyme-like cascade reactions in homochiral CuMOF pockets. The increased enzyme-like activity under LSPR excitation enhanced the identification performance.
Due to the obvious advantage in potassium reserves, potassium‐ion batteries (PIBs) are now receiving increasing research attention as an alternative energy storage system for lithium‐ion batteries ...(LIBs). Unfortunately, the large size of K+ makes it a challenging task to identify suitable electrode materials, particularly cathode ones that determine the energy density of PIBs, capable of tolerating the serious structural deformation during the continuous intercalation/deintercalation of K+. It is therefore of paramount importance that proper design principles of cathode materials be followed to ensure stable electrochemical performance if a practical application of PIBs is expected. Herein, the current knowledge on the structural engineering of cathode materials acquired during the battle against its performance degradation is summarized. The K+ storage behavior of different types of cathodes is discussed in detail and the structure–performance relationship of materials sensitive to their different lattice frameworks is highlighted. The key issues facing the future development of different categories of cathode materials are also highlighted and perspectives for potential approaches and strategies to promote the further development of PIBs are provided.
Potassium‐ion batteries (PIBs) are now receiving increasing research attention due to their obvious advantage regarding the potassium reserves. Cathode materials, which determine the energy density of PIBs, usually suffer from serious structural deformation during continuous K+ (de)intercalation. Therefore, proper structural‐design principles of cathode materials should be focused on to ensure high performance to promote the further development of PIBs.
A sensor with a red‐emission signal is successfully obtained by the solvothermal reaction of Eu3+ and heterofunctional ligand bpydbH2 (4,4′‐(4,4′‐bipyridine‐2,6‐diyl) dibenzoic acid), followed by ...terminal‐ligand exchange in a single‐crystal‐to‐single‐crystal transformation. As a result of treatments both before and after the metal–organic framework formation, accessible Lewis‐base sites and coordinated water molecules are successfully anchored onto the host material, and they act as signal transmission media for the recognition of analytes at the molecular level. This is the first reported sensor based on a metal–organic framework (MOF) with multi‐responsive optical sensing properties. It is capable of sensing small organic molecules and inorganic ions, and unprecedentedly it can discriminate among the homologues and isomers of aliphatic alcohols as well as detect highly explosive 2,4,6‐trinitrophenol (TNP) in water or in the vapor phase. This work highlights the practical application of luminescent MOFs as sensors, and it paves the way toward other multi‐responsive sensors by demonstrating the incorporation of various functional groups into a single framework.
Multi‐responsive fluorescent sensing is achieved using a Eu metal–organic framework (EuMOF). Accessible Lewis‐base sites and coordinated water molecules are successfully anchored on the EuMOF‐based sensor for the recognition of different analytes at the molecular level. This strategy paves the way for the practical application of luminescent MOF sensors in pollutant‐detection.
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