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Carbon materials/MXenes composite materials have gained widespread attention in the field of supercapacitors due to their excellent electrochemical performance. Carbon materials are considered ideal electrode materials for supercapacitors due to their high specific surface area, good conductivity, and outstanding electrochemical stability. MXenes, as a novel two-dimensional material, exhibit prominent conductivity, mechanical properties, and ionic conductivity, thereby showing great potential for applications in energy storage devices. The combination of carbon materials and MXenes is expected to fully leverage the advantages of both, optimizing electrode conductivity, enhancing the energy density and power density, and improving the charge–discharge performance. This article reviews the key research progress of carbon/MXenes composite materials in supercapacitors in recent years, including their synthesis methods, structural tuning, and improvements in their electrochemical performance. Finally, the article looks forward to future research directions and proposes potential strategies to enhance the overall performance of the composite materials and achieve large-scale applications. By addressing the existing challenges, carbon/MXenes composite materials are anticipated to achieve higher energy and power outputs for the supercapacitor field in the future, providing strong support for the development of new energy storage technologies such as electric vehicles and wearable devices. [ABSTRACT FROM AUTHOR]

Layered double hydroxides (LDHs) are promising catalysts for water electrolysis. Many efficient LDHs have been produced by adjusting their composition and structure. Herein, by using only sodium carbonate as a precipitator, we prepared gram-scale CoFe LDHs rich in carbonate anions depending on the incomplete double hydrolysis between carbonate and metal ions under atmospheric pressure. Owing to the flexible iron valence state, the coordination environment, and electronic structure of cobalt and iron in CoFe LDHs can be modified. The catalytic performance was substantially improved for the oxygen evolution reaction (OER) owing to the exposure of more metal active sites and the increase in the charge transfer rate. By adjusting the molar ratios of Co and Fe, Co1Fe1 LDH with excellent OER performance, which reached 10 mA cm−2 at an extremely low overpotential (270 mV) and a very low Tafel slope (42.7 mV dec−1), was obtained. Our work can pave the way for low cost high-performance LDHs in water electrolysis. [ABSTRACT FROM AUTHOR]

The search for suitable synthesis methods and parameters capable of controlling the length, diameter, and yield of silver nanowires (AgNWs) is still an emerging strategy today. Therefore, a method for high-yield synthesis of long AgNWs via chromic chloride and a stable reaction environment was proposed. The results show that Cr3+ could restore the adsorbed atomic oxygen quickly and provide a high efficiency in the prevention of the oxidative etching, for the ion of Cr2+ oxidized to Cr3+ has a lower standard electrode potential, and a more stable reaction environment provided by the coupling method could avoid disturbing the growth of the {111} reactive sites of the wires; then, the yield and length of the AgNWs were improved. The length of the AgNWs was over 75 μm and even 160 μm; the yield of the AgNWs was over 90%, which provides the referable basis for the synthesis of ultralong AgNWs. [ABSTRACT FROM AUTHOR]

High-purity ultrafine platinum particles are widely used to fabricate platinum electrode oxygen sensors for automobiles and thick-film platinum resistance temperature elements. In this study, the near-spherical ultrafine Pt particles of high purity were synthesized by chemical purification, spray-drying, and ignition from crude Pt powder. Impurities in the initial Pt powder were eliminated by the 001×7 strong acid cation resin exchange column and precipitation treatment. Near-spherical (NH4)2PtCl6 particles were obtained after spray-drying, and then the microstructure and size of as-synthesized Pt particles were controlled by the ignition process. The influences of different heating temperatures during ignition treatment on the microstructure and size of Pt particles were investigated. The purity of as-synthesized Pt particles was higher than 99.999 wt%, and the average size was about 1.12 μm. The results indicate that high-purity ultrafine Pt particles can be efficiently synthesized by chemical refining. [ABSTRACT FROM AUTHOR]

p-Type YbCd2-xMgxSb2 (x = 0.1-0.8) Zintl phases are prepared by melting and annealing the elements (carbon crucible in evacuated quartz tube, 1. [ABSTRACT FROM AUTHOR]

Palladium–Platinum (Pd–Pt) alloys have excellent hydrogen isotope separation properties near room temperature compared to pure palladium (Pd), and are expected to be used as filling materials in thermal cyclic absorption (TCAP) columns. However, most studies on the thermodynamic and kinetic hydrogen isotope effects of hydrogen absorption/deuterium in Pd–Pt alloys have been conducted at temperatures of 273 K or above, with few studies involving the performance of TCAP in the cold-cycle operating temperature range (253 K–303 K). In this work, the performance of Pd-5wt.%Pt alloy for the absorption of hydrogen/deuterium at low temperatures (263 K–323 K) was investigated. The results show that the enthalpy and entropy of dissolution of hydrogen and deuterium in the α-phase of Pd-5wt.%Pt alloy are −11.77 kJ/mol (H), 104.00 J mol−1 K−1(H); −5.50 kJ/mol (D), 87.88 J mol−1 K−1 (D), respectively, which are lower than the enthalpy and entropy change values of pure Pd materials. The apparent reaction activation energies of protium and deuterium absorption are −4.14 kJ/mol (H 2) and −11.87 kJ/mol (D 2), respectively, which are lower than those of pure palladium. The excellent hydrogen isotope separation performance of Pd–Pt alloys may originate from the fast hydrogen absorption and discharge isotope kinetic performance. • The introduction of Pt affects the thermodynamic properties of palladium. • Catalytic dissociation of Pt and powder particle size affect the solid solution of Pd–Pt with hydrogen. • The Pt structure enhances the protium-deuterium separation at low H/Pd. • Negative apparent reaction activation energy for deuterium and deuterium absorption. [ABSTRACT FROM AUTHOR]

Review: 66 refs. [ABSTRACT FROM AUTHOR]

High-entropy alloy (HEA) nanomaterials have emerged as promising candidates as oxygen evolution reaction (OER) electrocatalyst to overcome the existing issues of the sluggish reaction kinetics and poor stability. In this study, Ir x RuCoCuNi HEA three-dimensional-nanoframeworks (3DNF) are prepared using a scalable approach-the spray-drying technique combined with thermal decomposition reduction (SD-TDR). The optimized catalyst, Ir 2 RuCoCuNi, demonstrates superior OER performance, with an overpotential of 264 mV at 10 mA cm -2 and a Tafel slope of 47 mV dec -1 , considerably surpassing the catalytic activity of commercial IrO 2 . Electrochemical data reveal high electron transfer efficiency and a significant electrochemically active surface area (ECSA), attributed to its 3DNF porous structure and favorable surface self-reconstruction into (oxy)hydroxides during the OER. While increasing Ir content enhances catalytic activity, economic analysis highlights compositions with reduced Ir content, such as IrRu 2 CoCuNi and IrRuCo 2 CuNi, as cost-effective alternatives for practical applications. These findings underscore the potential of HEA 3DNFs for industrial-scale electrocatalysis and provide insights into balancing performance and cost for next-generation OER catalysts., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)