Stimuli‐responsive DNA‐functionalized nano‐ and microcontainers composed of mesoporous SiO2 nanoparticles (MP SiO2 NPs), microcapsules, or micelles/vesicles act as carriers for the transport and ...release of drugs. The information encoded in the DNA sequences provides instructive information for the gating of drug‐loaded pores of MP SiO2 NPs, for the assembly and degradation of microcapsules or lipid–DNA micelles/vesicles, and for the targeting of nano‐/microcontainers to cancer cells. Different triggers are applied to release the drugs loaded in the nano‐/microcontainers by unlocking the pores of the MP SiO2 NPs or by degradation of the containers. These include the use of switchable DNA nanostructures (nucleic acid hairpins, i‐motif, G‐quadruplexes) and the implementation of chemical, thermal, or photonic stimuli. Also, catalytic processes stimulated by DNAzymes or enzymes are used to release drugs from the nano‐/microcontainers.
DNA gates: Stimuli‐responsive DNA‐functionalized nano‐ and microcontainers composed of mesoporous SiO2 nanoparticles, microcapsules, or micelles/vesicles act as drug carriers for targeted controlled release. Different stimuli such as chemical, photonic, thermal, and biocatalytic triggers are used to release the loaded drugs.
We report a novel modulation strategy by introducing transition metals into NiS2 nanosheets (NSs) to flexibly optimize the electronic configurations and atomic arrangement. The Co‐NiS2 NSs exhibit ...excellent hydrogen evolution reaction (HER) performance with an overpotential of 80 mV at j=10 mA cm−2 and long‐term stability of 90 h in alkaline media. The turnover frequencies (TOFs) of 0.55 and 4.1 s−1 at an overpotential of 100 and 200 mV also confirm their remarkable performance. DFT calculations reveal that the surface dopants abnormally sensitize surface Ni‐3d bands in the long‐range order towards higher electron‐transfer activity, acting as the electron‐depletion center. Meanwhile, the high lying surface S‐sites possess substantially high selectivity for splitting the adsorbing H2O that guarantee the high HER performance within alkaline conditions. This work opens opportunities for enhancing water splitting by atomic‐arrangement‐assisted electronic modulation via a facile doping strategy.
Co doped: Cobalt‐doped NiS2 nanosheets (NSs) with optimal eg1 electron configurations and enhanced Ni3+ content exhibit excellent activity and stability for the hydrogen evolution reaction (HER) in alkaline media. DFT results reveal that a Co‐NiS2 NSs surface abnormally sensitizes Ni‐3d bands towards higher electron‐transfer.
Manipulating the active species and improving the structural stabilization of sulfur‐containing catalysts during the OER process remain a tremendous challenge. Herein, we constructed NiO/NiS2 and ...Fe−NiO/NiS2 as catalyst models to study the effect of Fe doping. As expected, Fe−NiO/NiS2 exhibits a low overpotential of 270 mV at 10 mA cm−2. The accumulation of hydroxyl groups on the surface of materials after Fe doping can promote the formation of highly active NiOOH at a lower OER potential. Moreover, we investigated the level of corrosion of M−S bonds and compared the stability variation of M−S bonds with Fe at different locations. Interestingly, Fe bonded with S in the bulk as the sacrificial agent can alleviate the oxidation corrosion of partial Ni−S bonds and thus endow Fe−NiO/NiS2 long‐term durability. This work could motivate the community to focus more on resolving the corrosion of sulfur‐containing materials.
Bulk doped Fe not only accelerates the surface reconstruction of NiO/NiS2 into the active NiOOH phase at a lower oxygen evolution reaction (OER) overpotential but also alleviates the oxidation corrosion of partial Ni−S bonds to provide a promising way to balance the activity and stability of sulfur‐containing materials in the OER process.
The proton exchange membrane (PEM) water electrolysis is one of the most promising hydrogen production techniques. The oxygen evolution reaction (OER) occurring at the anode dominates the overall ...efficiency. Developing active and robust electrocatalysts for OER in acid is a longstanding challenge for PEM water electrolyzers. Most catalysts show unsatisfied stability under strong acidic and oxidative conditions. Such a stability challenge also leads to difficulties for a better understanding of mechanisms. This review aims to provide the current progress on understanding of OER mechanisms in acid, analyze the promising strategies to enhance both activity and stability, and summarize the state‐of‐the‐art catalysts for OER in acid. First, the prevailing OER mechanisms are reviewed to establish the physicochemical structure–activity relationships for guiding the design of highly efficient OER electrocatalysts in acid with stable performance. The reported approaches to improve the activity, from macroview to microview, are then discussed. To analyze the problem of instability, the key factors affecting catalyst stability are summarized and the surface reconstruction is discussed. Various noble‐metal‐based OER catalysts and the current progress of non‐noble‐metal‐based catalysts are reviewed. Finally, the challenges and perspectives for the development of active and robust OER catalysts in acid are discussed.
Developing proton exchange membrane water electrolyzers requires a fundamental understanding of the oxygen evolution reaction (OER) in acid, which is the primary focus of this review. The water electrolyzer in alkaline and acid are compared; and the recent advances in OER mechanisms, the strategies for enhancing activity and stability of electrocatalysts, surface reconstruction, and the state‐of‐the‐art electrocatalysts are discussed.
Herein, a strategy is reported for the fabrication of NiCo2O4‐based mesoporous nanosheets (PNSs) with tunable cobalt valence states and oxygen vacancies. The optimized NiCo2.148O4 PNSs with an ...average Co valence state of 2.3 and uniform 4 nm nanopores present excellent catalytic performance with an ultralow overpotential of 190 mV at a current density of 10 mA cm−2 and long‐term stability (700 h) for the oxygen evolution reaction (OER) in alkaline media. Furthermore, Zn–air batteries built using the NiCo2.148O4 PNSs present a high power and energy density of 83 mW cm−2 and 910 Wh kg−1, respectively. Moreover, a portable battery box with NiCo2.148O4 PNSs as the air cathode presents long‐term stability for 120 h under low temperatures in the range of 0 to −35 °C. Density functional theory calculations reveal that the prominent electron exchange and transfer activity of the electrocatalyst is attributed to the surface lower‐coordinated Co‐sites in the porous region presenting a merging 3d–eg–t2g band, which overlaps with the Fermi level of the Zn–air battery system. This favors the adsorption of the *OH, and stabilized *O radicals are reached, toward competitively lower overpotential, demonstrating a generalized key for optimally boosting overall OER performance.
Optimized NiCo2.148O4 mesoporous nanosheets with an average Co valence state of 2.3 and uniform 4 nm mesopores demonstrate exceptional performance for Zn–air batteries under a wide temperature range from 80 to −35 °C, which arises from the high activities of electron exchange and transfer by the surface lower‐coordinated Co‐sites within the porous region.
Graphene Platform for Sensing Biomolecules Lu, Chun-Hua; Yang, Huang-Hao; Zhu, Chun-Ling ...
Angewandte Chemie (International ed.),
June 15, 2009, Letnik:
48, Številka:
26
Journal Article
Recenzirano
Sensitive platform: The use of graphene oxide (GO) as a platform for the sensitive and selective detection of DNA and proteins is presented. The interaction of GO and dye-labeled single-stranded DNA ...leads to quenching of the dye fluorescence. Conversely, the presence of a target DNA or protein leads to the binding of the dye-labeled DNA and target, releasing the DNA from GO, thereby restoring the dye fluorescence (see picture).
Anti‐counterfeiting techniques have become a global topic since they is correlated to the information and data safety, in which multimodal luminescence is one of the most desirable candidates for ...practical applications. However, it is a long‐standing challenge to actualize robust multimodal luminescence with high thermal stability and humid resistance. Conventionally, the multimodal luminescence is usually achieved by the combination of upconversion and downshifting luminescence, which only responds to the electromagnetic waves in a limited range. Herein, the Yb3+/Er3+/Bi3+ co‐doped Cs2Ag0.6Na0.4InCl6 perovskite material is reported as an efficient multimodal luminescence material. Beyond the excitation of ultraviolet light and near‐infrared laser (980 nm), this work extends multimodal luminescence to the excitation of X‐ray. Besides the flexible excitation sources, this material also shows the exceptional luminescence performance, in which the X‐ray detection limit reaches the level of nGy s−1, indicating a great potential for further application as a colorless pigment in the anti‐counterfeiting field. More importantly, the obtained double perovskite features high stability against both humidity and temperature up to 400 °C. This integrated multifunctional luminescent material provides a new directional solution for the development of multifunctional optical materials and devices.
A Yb3+/Er3+/Bi3+ co‐doped Cs2Ag0.6Na0.4InCl6 double‐perovskite material shows multi‐modal luminescence under excitation by X‐rays, ultraviolet light, and near‐infrared laser light (980 nm), which also features high stability against humidity and high temperature (up to 400 °C). This luminescent material further extends the functionality and potential for future commercial applications in anti‐counterfeiting and X‐ray detection.
Graphitic carbon nitrides (g‐C3N4) are a class of 2D polymeric materials mainly composed of carbon and nitrogen atoms. g‐C3N4 are attracting dramatically increasing interest in the areas of sensing, ...imaging, and therapy, due to their unique optical and electronic properties. Here, the luminescent properties (mainly includes photoluminescence and electrochemiluminescence), and catalytic and photoelectronic properties related to sensing and therapy applications of g‐C3N4 materials are reviewed. Furthermore, the fabrication and advantages of sensing, imaging and therapy systems based on g‐C3N4 materials are summarized. Finally, the future perspectives for developing the sensing, imaging and therapy applications of the g‐C3N4 materials are discussed.
The sensing, imaging and therapy applications of g‐C3N4 materials are summarized. The luminescent, catalytic and photoelectronic properties and mechanisms of g‐C3N4 materials related to sensing and therapy applications are introduced and discussed. The principles and advantages of the sensing, imaging and therapy systems are concluded.
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