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Nickel
\"When you think of nickel, a 5-cent coin probably comes to mind. But nickel is used for so much more than manufacturing coins. Nickel and nickel-containing alloys are very important in our society. Nickel is used in the construction, transportation, power, high-tech and many other industries. This book tells the fascinating story of how nickel was discovered, how ore containing nickel is mined and extracted, the properties that make nickel so useful, and how nickel's many uses and applications make the high-tech world we live in possible. It also provides students with up-to-date resources to continue their research.\"-- Provided by publisher.
Book
Rare-earth–platinum alloy nanoparticles in mesoporous zeolite for catalysis
Platinum is a much used catalyst that, in petrochemical processes, is often alloyed with other metals to improve catalytic activity, selectivity and longevity
1
–
5
. Such catalysts are usually prepared in the form of metallic nanoparticles supported on porous solids, and their production involves reducing metal precursor compounds under a H
2
flow at high temperatures
6
. The method works well when using easily reducible late transition metals, but Pt alloy formation with rare-earth elements through the H
2
reduction route is almost impossible owing to the low chemical potential of rare-earth element oxides
6
. Here we use as support a mesoporous zeolite that has pore walls with surface framework defects (called ‘silanol nests’) and show that the zeolite enables alloy formation between Pt and rare-earth elements. We find that the silanol nests enable the rare-earth elements to exist as single atomic species with a substantially higher chemical potential compared with that of the bulk oxide, making it possible for them to diffuse onto Pt. High-resolution transmission electron microscopy and hydrogen chemisorption measurements indicate that the resultant bimetallic nanoparticles supported on the mesoporous zeolite are intermetallic compounds, which we find to be stable, highly active and selective catalysts for the propane dehydrogenation reaction. When used with late transition metals, the same preparation strategy produces Pt alloy catalysts that incorporate an unusually large amount of the second metal and, in the case of the PtCo alloy, show high catalytic activity and selectivity in the preferential oxidation of carbon monoxide in H
2
.
Alloy nanoparticles of platinum and rare-earth elements are formed using zeolites with pore-wall defects, producing stable, highly active and selective catalysts for the propane dehydrogenation reaction.
Journal Article
Recent Advances of Transition Metal Basic Salts for Electrocatalytic Oxygen Evolution Reaction and Overall Water Electrolysis
HighlightsWe summarize the recent advances of transition metal basic salts and their application in oxygen evolution reaction (OER) and further overall water splitting.The structure evolution of transition metal basic salts during OER and the impact of F−, Cl−, CO32− and NO3− on the OER performance are highlightedElectrocatalytic oxygen evolution reaction (OER) has been recognized as the bottleneck of overall water splitting, which is a promising approach for sustainable production of H2. Transition metal (TM) hydroxides are the most conventional and classical non-noble metal-based electrocatalysts for OER, while TM basic salts [M2+(OH)2-x(Am−)x/m, A = CO32−, NO3−, F−, Cl−] consisting of OH− and another anion have drawn extensive research interest due to its higher catalytic activity in the past decade. In this review, we summarize the recent advances of TM basic salts and their application in OER and further overall water splitting. We categorize TM basic salt-based OER pre-catalysts into four types (CO32−, NO3−, F−, Cl−) according to the anion, which is a key factor for their outstanding performance towards OER. We highlight experimental and theoretical methods for understanding the structure evolution during OER and the effect of anion on catalytic performance. To develop bifunctional TM basic salts as catalyst for the practical electrolysis application, we also review the present strategies for enhancing its hydrogen evolution reaction activity and thereby improving its overall water splitting performance. Finally, we conclude this review with a summary and perspective about the remaining challenges and future opportunities of TM basic salts as catalysts for water electrolysis.
Journal Article
From VIB- to VB-Group Transition Metal Disulfides: Structure Engineering Modulation for Superior Electromagnetic Wave Absorption
HighlightsA systematic summary of current research trends in the development of transition metal disulfides (TMDs) electromagnetic wave (EMW) absorption materials.In-depth comparisons on the structures, preparation methods, application merits of VIB- and VB-group TMDs.Structure engineering modulation of TMDs in achieving superior EMW absorption is outlined from the viewpoints of heterostructures, defects, morphologies, and phases.Exclusive insights into the challenges, strategies, and opportunities in the design of EMW absorption materials with outstanding performance are provided.The laminated transition metal disulfides (TMDs), which are well known as typical two-dimensional (2D) semiconductive materials, possess a unique layered structure, leading to their wide-spread applications in various fields, such as catalysis, energy storage, sensing, etc. In recent years, a lot of research work on TMDs based functional materials in the fields of electromagnetic wave absorption (EMA) has been carried out. Therefore, it is of great significance to elaborate the influence of TMDs on EMA in time to speed up the application. In this review, recent advances in the development of electromagnetic wave (EMW) absorbers based on TMDs, ranging from the VIB group to the VB group are summarized. Their compositions, microstructures, electronic properties, and synthesis methods are presented in detail. Particularly, the modulation of structure engineering from the aspects of heterostructures, defects, morphologies and phases are systematically summarized, focusing on optimizing impedance matching and increasing dielectric and magnetic losses in the EMA materials with tunable EMW absorption performance. Milestones as well as the challenges are also identified to guide the design of new TMDs based dielectric EMA materials with high performance.
Journal Article
Recent advances of transition‐metal metaphosphates for efficient electrocatalytic water splitting
Sustainable production of H2 through electrochemical water splitting is of great importance in the foreseeable future. Transition‐metal metaphosphates (TMMPs) have a three‐dimensional (3D) open‐framework structure and a high content of P (which exists as PO3−), and therefore have been recognized as highly efficient catalysts for oxygen evolution reaction (OER) and the bottleneck of electrochemical water splitting. Furthermore, TMMPs can also contribute to hydrogen evolution reaction (HER) in alkaline and neutral media by facilitating water dissociation, and thus, overall water splitting can be achieved using this kind of material. In this timely review, we summarize the recent advances in the synthesis of TMMPs and their applications in OER and HER. We present a brief introduction of the structure and synthetic strategies of TMMPs in the first two parts. Then, we review the latest progress made in research on TMMPs as OER, HER, and overall water‐splitting electrocatalysts. In this part, the intrinsic activity of TMMPs as well as the current strategy for improving the catalytic activity will be discussed systematically. Finally, we present the future opportunities and the remaining challenges for the application of TMMPs in the electrocatalysis field. Transition‐metal metaphosphates (TMMPs) have a three‐dimensional open‐framework structure and a high content of P (which exists as PO3−), and therefore have been recognized as highly efficient catalysts for oxygen evolution reaction, the bottleneck of electrochemical water splitting. Furthermore, TMMPs can also contribute to hydrogen evolution reaction in alkaline and neutral media by facilitating water dissociation, and thus, overall water splitting can be achieved using this kind of material.
Journal Article
Advanced materials and technologies for supercapacitors used in energy conversion and storage: a review
Supercapacitors are increasingly used for energy conversion and storage systems in sustainable nanotechnologies. Graphite is a conventional electrode utilized in Li-ion-based batteries, yet its specific capacitance of 372 mA h g−1 is not adequate for supercapacitor applications. Interest in supercapacitors is due to their high-energy capacity, storage for a shorter period and longer lifetime. This review compares the following materials used to fabricate supercapacitors: spinel ferrites, e.g., MFe2O4, MMoO4 and MCo2O4 where M denotes a transition metal ion; perovskite oxides; transition metals sulfides; carbon materials; and conducting polymers. The application window of perovskite can be controlled by cations in sublattice sites. Cations increase the specific capacitance because cations possess large orbital valence electrons which grow the oxygen vacancies. Electrodes made of transition metal sulfides, e.g., ZnCo2S4, display a high specific capacitance of 1269 F g−1, which is four times higher than those of transition metals oxides, e.g., Zn–Co ferrite, of 296 F g−1. This is explained by the low charge-transfer resistance and the high ion diffusion rate of transition metals sulfides. Composites made of magnetic oxides or transition metal sulfides with conducting polymers or carbon materials have the highest capacitance activity and cyclic stability. This is attributed to oxygen and sulfur active sites which foster electrolyte penetration during cycling, and, in turn, create new active sites.
Journal Article
Recent Progress in Emerging Two-Dimensional Transition Metal Carbides
HighlightsThe phase diagram of transition metal carbides (TMCs) is discussed.The physical and chemical property of TMCs is systematically summarized.The potential application and controllable synthesis of TMCs is discussed.A summary is provided to afford the principle to further investigation.As a new member in two-dimensional materials family, transition metal carbides (TMCs) have many excellent properties, such as chemical stability, in-plane anisotropy, high conductivity and flexibility, and remarkable energy conversation efficiency, which predispose them for promising applications as transparent electrode, flexible electronics, broadband photodetectors and battery electrodes. However, up to now, their device applications are in the early stage, especially because their controllable synthesis is still a great challenge. This review systematically summarized the state-of-the-art research in this rapidly developing field with particular focus on structure, property, synthesis and applicability of TMCs. Finally, the current challenges and future perspectives are outlined for the application of 2D TMCs.
Journal Article
High phase-purity 1T′-MoS2- and 1T′-MoSe2-layered crystals
Phase control plays an important role in the precise synthesis of inorganic materials, as the phase structure has a profound influence on properties such as conductivity and chemical stability. Phase-controlled preparation has been challenging for the metallic-phase group-VI transition metal dichalcogenides (the transition metals are Mo and W, and the chalcogens are S, Se and Te), which show better performance in electrocatalysis than their semiconducting counterparts. Here, we report the large-scale preparation of micrometre-sized metallic-phase 1T′-MoX2 (X = S, Se)-layered bulk crystals in high purity. We reveal that 1T′-MoS2 crystals feature a distorted octahedral coordination structure and are convertible to 2H-MoS2 following thermal annealing or laser irradiation. Electrochemical measurements show that the basal plane of 1T′-MoS2 is much more active than that of 2H-MoS2 for the electrocatalytic hydrogen evolution reaction in an acidic medium.
Journal Article
Unified picture of anionic redox in Li/Na-ion batteries
Anionic redox in Li-rich and Na-rich transition metal oxides (A-rich-TMOs) has emerged as a new paradigm to increase the energy density of rechargeable batteries. Ever since, numerous electrodes delivering extra anionic capacity beyond the theoretical cationic capacity have been reported. Unfortunately, most often the anionic capacity achieved in charge is partly irreversible in discharge. A unified picture of anionic redox in A-rich-TMOs is designed here to identify the electronic origin of this irreversibility and to propose new directions to improve the cycling performance of the electrodes. The electron localization function is introduced as a holistic tool to unambiguously locate the oxygen lone pairs in the structure and follow their participation in the redox activity of A-rich-TMOs. The charge-transfer gap of transition metal oxides is proposed as the pertinent observable to quantify the amount of extra capacity achievable in charge and its reversibility in discharge, irrespective of the material chemical composition. From this generalized approach, we conclude that the reversibility of the anionic capacity is limited to a critical number of O holes per oxygen, hO ≤ 1/3.Although anionic redox in Li- and Na-rich transition metal oxides can enhance energy density of rechargeable batteries, anionic capacity is partly irreversible in discharge. A unified picture to clarify this irreversibility and to improve cycling performance is proposed.
Journal Article
Electrochemical Sensors Based on Transition Metal Materials for Phenolic Compound Detection
Electrochemical sensors have been recognized as crucial tools for monitoring comprehensive chemical information, especially in the detection of a significant class of molecules known as phenolic compounds. These compounds can be present in water as hazardous analytes and trace contaminants, as well as in living organisms where they regulate their metabolism. The sensitive detection of phenolic compounds requires highly efficient and cost-effective electrocatalysts to enable the development of high-performance sensors. Therefore, this review focuses on the development of advanced materials with excellent catalytic activity as alternative electrocatalysts to conventional ones, with a specific emphasis on transition metal-based electrocatalysts for the detection of phenolic compounds. This research is particularly relevant in diverse sectors such as water quality, food safety, and healthcare.
Journal Article