Poly(acrylic acid) (PAA) is added as a binder to the water-based slurry of Ni-rich Li(Ni0.8Co0.1Mn0.1)O2 (NCM811) powder. After adding PAA, the pH of the slurry changes from strongly alkaline to ...nearly neutral (pH9.0), making it suitable for casting on the aluminum current collector without corroding the aluminum (Al) and a largely increased adhesion from 318 to 458 kg m−2 after drying. The use of PAA also improves the dispersion of the slurry, because the carboxyl groups of PAA can interact with NCM811 to help stabilize the electrode particles in the slurry. Given the improved dispersion, reduced corrosion potential, and better adhesion, the resultant NCM811 cathode exhibits good structural integrity and greatly lowered charge-transfer resistance from 37.0 to 8.5 , showing a high initial capacity of 189.2 mAh g−1 and capacity retention of 84.2% after 100 charge-discharge cycles under 0.2C.
Surface-functionalized gold and silver nanoparticles are promising nanosensors for applications in the environmental and biological fields. In this review, various organic chelating ...receptors-functionalized gold and silver nanoparticles as sensing materials are systematically summarized and discussed from their attached receptor structures to their applications in metal ions and biomolecules sensing.
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•Surface functionalized AuNPs and AgNPs-based colorimetric and fluorometric sensors are reviewed.•AuNPs and AgNPs-based colorimetric and fluorometric sensors for metal ions and biomolecules sensing applications are discussed.•This review analyzes and summarizes the structure of various organic chelating motifs.•Conclusion and Future Perspective on using surface-functionalized AuNPs and AgNPs in visual sensing applications.
Surface-functionalized gold and silver nanoparticles, AuNPs and AgNPs for short, prepared via the modification of organic chelating motifs by covalent or non-covalent bonds, represent an ideal type of hybrid nanomaterials that attract widespread attention because of their outstanding advantages, including exceptional optical, electrical, and photothermal properties, and more importantly, specific surface plasmon resonance (SPR) property in well-dispersed solutions. In recent years, AuNPs and AgNPs modified with functional organic chelating receptors have been extensively studied as robust colorimetric and fluorescent sensors, showing broad application prospects in pollutant detection, trace analysis, and other related research fields. Therefore, this review article outlines various AuNPs and AgNPs equipped with thiol-based organic molecules, amino acids, biomolecules, and fluorophores for colorimetric and fluorescent sensing towards toxic metal ions and essential biomolecules. Certain other types of gold and silver nanomaterials are also covered, such as gold nanoclusters (AuNCs), silver nanoclusters (AgNCs), and silver quantum clusters (AgQCs).
In the absence of high-resolution estimates of the components of surface energy balance for China, we developed an algorithm based on the surface energy balance system (SEBS) to generate a data set ...of land-surface energy and water fluxes on a monthly timescale from 2001 to 2010 at a 0.1 × 0.1° spatial resolution by using multi-satellite and meteorological forcing data. A remote-sensing-based method was developed to estimate canopy height, which was used to calculate roughness length and flux dynamics. The land-surface flux data set was validated against "ground-truth" observations from 11 flux tower stations in China. The estimated fluxes correlate well with the stations' measurements for different vegetation types and climatic conditions (average bias = 11.2 Wm−2, RMSE = 22.7 Wm−2). The quality of the data product was also assessed against the GLDAS data set. The results show that our method is efficient for producing a high-resolution data set of surface energy flux for the Chinese landmass from satellite data. The validation results demonstrate that more accurate downward long-wave radiation data sets are needed to be able to estimate turbulent fluxes and evapotranspiration accurately when using the surface energy balance model. Trend analysis of land-surface radiation and energy exchange fluxes revealed that the Tibetan Plateau has undergone relatively stronger climatic change than other parts of China during the last 10 years. The capability of the data set to provide spatial and temporal information on water-cycle and land–atmosphere interactions for the Chinese landmass is examined. The product is free to download for studies of the water cycle and environmental change in China.
Catalysis informatics is a distinct subfield that lies at the intersection of cheminformatics and materials informatics but with distinctive challenges arising from the dynamic, surface-sensitive, ...and multiscale nature of heterogeneous catalysis. The ideas behind catalysis informatics can be traced back decades, but the field is only recently emerging due to advances in data infrastructure, statistics, machine learning, and computational methods. In this work, we review the field from early works on expert systems and knowledge engines to more recent approaches utilizing machine-learning and uncertainty quantification. The data–information–knowledge hierarchy is introduced and used to classify various developments. The chemical master equation and microkinetic models are proposed as a quantitative representation of catalysis knowledge, which can be used to generate explanative and predictive hypotheses for the understanding and discovery of catalytic materials. We discuss future prospects for the field, including improved quantitative coupling of experiment/theory, advanced microkinetic models, and the development of open-source software tools. Ultimately, integration of existing chemical and physical models with emerging statistical and computational tools presents a promising route toward the automated design, discovery, and optimization of heterogeneous catalytic processes.
The early stages of oxidation on Ni(111) and Ni-18 wt%Cr(111) surfaces were studied with scanning tunneling microscopy/spectroscopy. After exposure to oxygen at 500 °C, chemisorbed p(2 ×2)O adlayers ...appear on Ni(111) without oxide formation. On the Ni-Cr(111) surface 2D NiO(100) layers rapidly accumulate on the terraces. These coexist with Cr-rich clusters, which coalesce as oxidation progresses. Larger oxide nodules with 3D-island morphology are identified as chromia and are found embedded in the NiO(100). Spectroscopy reveals electronic heterogeneity, highlighting the chemical variation between each oxide species. A schematic is constructed that highlights the associated Ni- and Cr- reaction pathways on Ni-Cr(111) alloy surfaces.
•Scanning tunneling microscopy (STM) and spectroscopy (STS) reveals the oxidation behavior on Ni(111) and Ni-Cr(111) alloy surfaces•Ni oxidation pathway initiates with rapid growth of 2D NiO(100) layers•Cr oxidation pathway initiates with the formation of Cr-rich particles, followed by Cr-oxide 3D island growth•Electronic structure of oxide surface underscores chemical and compositional heterogeneity across oxide layers
One of the most remarkable and exciting achievements in the field of scanning probe microscopy (SPM) in the last years is the unprecedented sub-molecular resolution of both atomic and electronic ...structures of single molecules deposited on solid state surfaces. Despite its youth, the technique has already brought many new possibilities to perform different kinds of measurements, which cannot be accomplished by other techniques. This opens new perspectives in advanced characterization of physical and chemical processes and properties of molecular structures on surfaces. Here, we discuss the history and recent progress of the high resolution imaging with a functionalized probe by means of atomic force microscopy (AFM), scanning tunnelling microscopy (STM) and inelastic electron tunneling spectroscopy (IETS). We describe the mechanisms responsible for the high-resolution AFM, STM and IETS-STM contrast. The complexity of this technique requires new theoretical approaches, where a relaxation of the functionalized probe is considered. We emphasise the similarities of the mechanism driving high-resolution SPM with other imaging methods. We also summarise briefly significant achievements and progress in different branches. Finally we provide brief perspectives and remaining challenges of the further refinement of these high-resolution methods.
Design and synthesis of active, stable and cost-effective materials for efficient hydrogen production (hydrogen evolution reaction, HER) is of paramount importance for the successful deployment of ...hydrogen-based alternative energy technologies. The HER, seemingly one of the simplest electrochemical reactions, has served for decades to bridge the gap between fundamental electrocatalysis and practical catalyst design. However, there are still many open questions that need to be answered before it would be possible to claim that design principles of catalyst materials are fully developed for the efficient hydrogen production. In this review, by summarizing key results for the HER on well-characterized electrochemical interfaces in acidic and alkaline media, we have broadened our understanding of the HER in the whole range of pH by considering three main parameters: the nature of the proton donor (H3O+ in acid and H2O in alkaline), the energy of adsorption of Had and OHad, and the presence of spectator species. Simply by considering these three parameters we show that great deal has already been learned and new trends are beginning to emerge, giving some predictive ability with respect to the nature of electrochemical interface and electrocatalytic activity of the HER.
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•An overview of design principles for hydrogen evolution reaction (HER) is presented.•The role of pH is explored to demonstrate importance of water dissociation.•Together with substrate–Had interactions, the role of other possible descriptor is discussed.•Bi-functional mode of action is proposed for HER in alkaline media.•Balance between M–Had and M–OHad is necessary for optimizing efficiency for hydrogen production.
The junctions formed at the contact between metallic electrodes and semiconductor materials are crucial components of electronic and optoelectronic devices
. Metal-semiconductor junctions are ...characterized by an energy barrier known as the Schottky barrier, whose height can, in the ideal case, be predicted by the Schottky-Mott rule
on the basis of the relative alignment of energy levels. Such ideal physics has rarely been experimentally realized, however, because of the inevitable chemical disorder and Fermi-level pinning at typical metal-semiconductor interfaces
. Here we report the creation of van der Waals metal-semiconductor junctions in which atomically flat metal thin films are laminated onto two-dimensional semiconductors without direct chemical bonding, creating an interface that is essentially free from chemical disorder and Fermi-level pinning. The Schottky barrier height, which approaches the Schottky-Mott limit, is dictated by the work function of the metal and is thus highly tunable. By transferring metal films (silver or platinum) with a work function that matches the conduction band or valence band edges of molybdenum sulfide, we achieve transistors with a two-terminal electron mobility at room temperature of 260 centimetres squared per volt per second and a hole mobility of 175 centimetres squared per volt per second. Furthermore, by using asymmetric contact pairs with different work functions, we demonstrate a silver/molybdenum sulfide/platinum photodiode with an open-circuit voltage of 1.02 volts. Our study not only experimentally validates the fundamental limit of ideal metal-semiconductor junctions but also defines a highly efficient and damage-free strategy for metal integration that could be used in high-performance electronics and optoelectronics.
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