Oxygen evolution reaction （OER） electrolysis, as an important reaction involved in water splitting and rechargeable metal-air batteries, has attracted increasing attention for clean energy generation ...and efficient energy storage. Nickel/iron （NiFe）-based compounds have been known as active OER catalysts since the last century, and renewed interest has been witnessed in recent years on developing advanced NiFe-based materials for better activity and stability. In this review, we present the early discovery and recent progress on NiFe-based OER electrocatalysts in terms of chemical properties, synthetic methodologies and catalytic performances. The advantages and disadvantages of each class of NiFe-based compounds are summarized, including NiFe alloys, electrodeposited films and layered double hydroxide nanoplates. Some mechanistic studies of the active phase of NiFe-based compounds are introduced and discussed to give insight into the nature of active catalytic sites, which could facilitate further improving NiFe based OER electrocatalysts. Finally, some applications of NiFe- based compounds for OER are described, including the development of an electrolyzer operating with a single AAA battery with voltage below 1.5 V and high performance rechargeable Zn-air batteries.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The global shift of energy production from fossil fuels to renewable energy sources requires more efficient and reliable electrochemical energy storage devices. In particular, the development of ...electric or hydrogen powered vehicles calls for much-higher-performance batteries, supercapacitors and fuel cells than are currently available. In this review, we present an approach to synthesize electrochemical energy storage materials to form strongly coupled hybrids (SC-hybrids) of inorganic nanomaterials and novel graphitic nano-carbon materials such as carbon nanotubes and graphene, through nucleation and growth of nanoparticles at the functional groups of oxidized graphitic nano-carbon. We show that the inorganic-nano-carbon hybrid materials represent a new approach to synthesize electrode materials with higher electrochemical performance than traditional counterparts made by simple physical mixtures of electrochemically active inorganic particles and conducting carbon materials. The inorganic-nano-carbon hybrid materials are novel due to possible chemical bonding between inorganic nanoparticles and oxidized carbon, affording enhanced charge transport and increased rate capability of electrochemical materials without sacrificing specific capacity. Nano-carbon with various degrees of oxidation provides a novel substrate for nanoparticle nucleation and growth. The interactions between inorganic precursors and oxidized-carbon substrates provide a degree of control over the morphology, size and structure of the resulting inorganic nanoparticles. This paper reviews the recent development of inorganic-nano-carbon hybrid materials for electrochemical energy storage and conversion, including the preparation and functionalization of graphene sheets and carbon nanotubes to impart oxygen containing groups and defects, and methods of synthesis of nanoparticles of various morphologies on oxidized graphene and carbon nanotubes. We then review the applications of the SC-hybrid materials for high performance lithium ion batteries, rechargeable Li-S and Li-O2 batteries, supercapacitors and ultrafast Ni-Fe batteries, and new electrocatalysts for oxygen reduction, oxygen evolution and hydrogen evolution reactions.
Rare-earth (RE) based luminescent probes exhibit rich optical properties including upconversion and down-conversion luminescence spanning a broad spectral range from 300 to 3,000 nm, and have ...generated great scientific and practical interest from telecommunication to biological imaging. While upconversion nanoparticles have been investigated for decades, down-conversion luminescence of RE-based probes in the second near-infrared (NIR-II, 1,000–1,700 nm) window for
in vivo
biological imaging with sub-centimeter tissue penetration and micrometer image resolution has come into light only recently. In this review, we present recent progress on RE-based NIR-II probes for
in vivo
vasculature and molecular imaging with a focus on Er
3+
-based nanoparticles due to the down-conversion luminescence at the long-wavelength end of the NIR-II window (NIR-IIb, 1,500–1,700 nm). Imaging in NIR-IIb is superior to imaging with organic probes such as ICG and IRDye800 in the ~ 800 nm NIR range and the 1,000-1,300 nm short end of NIR-II range, owing to minimized light scattering and autofluorescence background. Doping by cerium and other ions and phase engineering of Er
3+
-based nanoparticles, combined with surface hydrophilic coating optimization can afford ultrabright, biocompatible NIR-IIb probe towards clinical translation for human use. The Nd
3+
-based probes with NIR-II emission at 1,050 and 1,330 nm are also discussed, including Nd
3+
doped nanocrystals and Nd
3+
-organic ligand complexes. This review also points out future directions for further development of multi-functional RE NIR-II probes for biological imaging.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In vivo near-infrared (NIR) fluorescence imaging is an emerging biomedical imaging modality for use in both fundamental scientific research and clinical practice. Owing to advances in reducing photon ...scattering, light absorption and autofluorescence through innovations in the broad 700–1,700 nm NIR window, NIR fluorescence affords high imaging resolution with increasing tissue penetration depths. In this Review, we cover recent progress made on NIR fluorescence imaging in both the 700–900 nm NIR-I and the 1,000–1,700 nm NIR-II windows by highlighting an increasingly developing palette of biocompatible NIR fluorophores that span the entire NIR window and include inorganic nanoparticles, organic macromolecules and small molecules with tunable emission wavelengths. Together with advances in imaging instrumentation allowing for the efficient detection of long-wavelength NIR photons, recently developed NIR fluorophores have fuelled biomedical imaging from contrast-enhanced imaging of anatomical structures and molecular imaging of specific biomarkers to functional imaging of physiological activities, both for preclinical animal studies and clinical diagnostics and interventions.This Review covers recent progress on near-infrared fluorescence imaging for preclinical animal studies and clinical diagnostics and interventions.
Large-scale graphene electronics requires lithographic patterning of narrow graphene nanoribbons for device integration. However, conventional lithography can only reliably pattern approximately ...20-nm-wide GNR arrays limited by lithography resolution, while sub-5-nm GNRs are desirable for high on/off ratio field-effect transistors at room temperature. Here, we devised a gas phase chemical approach to etch graphene from the edges without damaging its basal plane. The reaction involved high temperature oxidation of graphene in a slightly reducing environment in the presence of ammonia to afford controlled etch rate (less than or approximately 1 nm min(-1)). We fabricated approximately 20-30-nm-wide graphene nanoribbon arrays lithographically, and used the gas phase etching chemistry to narrow the ribbons down to <10 nm. For the first time, a high on/off ratio up to approximately 10(4) was achieved at room temperature for field-effect transistors built with sub-5-nm-wide graphene nanoribbon semiconductors derived from lithographic patterning and narrowing. Our controlled etching method opens up a chemical way to control the size of various graphene nano-structures beyond the capability of top-down lithography.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Fluorescence bioimaging affords a vital tool for both researchers and surgeons to molecularly target a variety of biological tissues and processes. This review focuses on summarizing organic dyes ...emitting at a biological transparency window termed the near‐infrared‐II (NIR‐II) window, where minimal light interaction with the surrounding tissues allows photons to travel nearly unperturbed throughout the body. NIR‐II fluorescence imaging overcomes the penetration/contrast bottleneck of imaging in the visible region, making it a remarkable modality for early diagnosis of cancer and highly sensitive tumor surgery. Due to their convenient bioconjugation with peptides/antibodies, NIR‐II molecular dyes are desirable candidates for targeted cancer imaging, significantly overcoming the autofluorescence/scattering issues for deep tissue molecular imaging. To promote the clinical translation of NIR‐II bioimaging, advancements in the high‐performance small molecule–derived probes are critically important. Here, molecules with clinical potential for NIR‐II imaging are discussed, summarizing the synthesis and chemical structures of NIR‐II dyes, chemical and optical properties of NIR‐II dyes, bioconjugation and biological behavior of NIR‐II dyes, whole body imaging with NIR‐II dyes for cancer detection and surgery, as well as NIR‐II fluorescence microscopy imaging. A key perspective on the direction of NIR‐II molecular dyes for cancer imaging and surgery is also discussed.
Among all existing near‐infrared (NIR)‐II fluorophores, the NIR‐II molecular dyes are the most remarkable in translating this imaging window into the clinical setting. Advanced NIR‐II dye‐derived bioconjugates will give doctors an unparalleled view into tissues for tumor detection at greater depths and contrast, allowing early detection during cancer screenings and solid tumor resection by delineation of the boundaries between healthy and cancerous tissues.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Electrochemical systems, such as fuel cell and water splitting devices, represent some of the most efficient and environmentally friendly technologies for energy conversion and storage. ...Electrocatalysts play key roles in the chemical processes but often limit the performance of the entire systems due to insufficient activity, lifetime, or high cost. It has been a long-standing challenge to develop efficient and durable electrocatalysts at low cost. In this Perspective, we present our recent efforts in developing strongly coupled inorganic/nanocarbon hybrid materials to improve the electrocatalytic activities and stability of inorganic metal oxides, hydroxides, sulfides, and metal–nitrogen complexes. The hybrid materials are synthesized by direct nucleation, growth, and anchoring of inorganic nanomaterials on the functional groups of oxidized nanocarbon substrates including graphene and carbon nanotubes. This approach affords strong chemical attachment and electrical coupling between the electrocatalytic nanoparticles and nanocarbon, leading to nonprecious metal-based electrocatalysts with improved activity and durability for the oxygen reduction reaction for fuel cells and chlor-alkali catalysis, oxygen evolution reaction, and hydrogen evolution reaction. X-ray absorption near-edge structure and scanning transmission electron microscopy are employed to characterize the hybrids materials and reveal the coupling effects between inorganic nanomaterials and nanocarbon substrates. Z-contrast imaging and electron energy loss spectroscopy at single atom level are performed to investigate the nature of catalytic sites on ultrathin graphene sheets. Nanocarbon-based hybrid materials may present new opportunities for the development of electrocatalysts meeting the requirements of activity, durability, and cost for large-scale electrochemical applications.
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IJS, KILJ, NUK, PNG, UL, UM
In the past decade, noticeable progress has been achieved regarding fluorescence imaging in the second near‐infrared (NIR‐II) window. Fluorescence imaging in the NIR‐II window demonstrates ...superiorities of deep tissue penetration and high spatial and temporal resolution, which are beneficial for profiling physiological processes. Meanwhile, molecular imaging has emerged as an efficient tool to decipher biological activities on the molecular and cellular level. Extending molecular imaging into the NIR‐II window would enhance the imaging performance, providing more detailed and accurate information of the biological system. In this progress report, selected achievements made in NIR‐II molecular imaging are summarized. The organization of this report is based on strategies underlying rational designs of NIR‐II imaging probes, and their applications in molecular imaging are highlighted. This progress report may provide guidance and reference for further development of functional NIR‐II probes designed for high‐performance molecular imaging.
Molecular imaging enables visualization and understanding of physiological activities on the cellular and molecular level. The extension of the molecular imaging window into the second near‐infrared (NIR‐II) window can better fulfill requirements of clinical applications. In this progress report, recent advances of NIR‐II molecular imaging are summarized, providing insights for future development of NIR‐II molecular imaging.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A look at how carbon nanomaterials are being utilized for nanomedicinal therapy and biological imaging. Topics discussed include carbon nanomaterials for biological imaging, carbon nanomaterials for ...nanomedicinal therapy and the pharmacokinetics and toxicology of carbon nanomaterials.
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IJS, KILJ, NUK, PNG, UL, UM
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