Structural, magnetic properties of in-plane chemically ordered (Mo2/3R)2AlC (R = Gd, Tb, Dy, Ho, Er and Y) MAX phase and enhanced capacitance of Mo1.33C MXene derivatives

Yang, Jiaxin; Yao, Guiquan; Sun, Shuli; Chen, Zhaohui; Yuan, Shuang; Kai, Wu; Fu, Xiaoxiao; Wang, Qiang; Cui, Weibin

doi:10.1016/j.carbon.2021.03.062

Cited by 25 publications

(15 citation statements)

References 33 publications

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“…Recently, MXenes with well-ordered MVs, such as W 1.33 C, [40] Nb 1.33 C, [41] and Mo 1.33 C, [42] have been synthesized by targeted etching of the A layers and M″-atoms from their parent quaternary (M′ 2/3 M″ 1/3 ) 2 AX phases, where the introduction of ordered basal-plane MVs can significantly tune the electrochemical behavior. [43] For instance, Rosen et al [44] experimentally synthesized W 1.33 C nanosheets by simultaneously removing the Al layers and interlayer Sc/Y from (W 2/3 M 1/3 ) 2 AlC (M = Sc and Y) precursors (Figure 3c,d).…”

Section: Atomic Vacancymentioning

confidence: 99%

MXene Nanoarchitectonics: Defect‐Engineered 2D MXenes towards Enhanced Electrochemical Water Splitting

Tang

Yang

et al. 2022

Advanced Energy Materials

167

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catalysts are currently widely utilized as the best performing HER and OER catalysts, respectively. But their high cost and scarcity seriously hinders their extensive implementation. Therefore, developing cost-effective alternatives and studying the electrocatalytic mechanisms of HER and OER catalysts is of practical significance and is economically desirable.2D transition metal (TM) carbides and nitrides, well-defined MXenes, constitute a thriving layered material family. MXenes are typically synthesized by extracting the "A" layers (A = Si, Al, Ga, etc.) from layered MAX (M n+1 AX n ) precursors. Generally, MXenes are described using the chemical formula M n+1 X n T z , where M refers to TM elements (such as Ti, V, Cr, and Mo); X represents C and/or N; T z stands for O, OH, F, Cl, Br surface terminals; [3,4] and n = 1, 2, 3, or 4. [5,6] In 2016, Seh et al. [7] used theoretical and experimental results to demonstrate that Mo 2 CT x could be an active and stable catalyst for HER, which inspired the blooming development of MXenes-based electrocatalysts. Theoretical predictions have indicated that MXenes are promising electrocatalysts owing to their high electrical conductivity, excellent hydrophilicity, large surface areas, tunable structures, and ultralow work functions. [8][9][10] However, the catalytic activities of most pristine MXenes do not perform well because they restack easily and have poor stability in oxidating environments. It has been proven that catalytic performance 2D MXenes-based nanoarchitectures are being actively explored for electrocatalytic water splitting because they possess physical and physiochemical properties that enhance catalytic activity toward the hydrogen evolution reaction and oxygen evolution reaction. This review systematically summarizes current strategies involved in defect engineering, including introducing atomic vacancies and active edges, and doping with metal and non-metal atoms, which have been employed to achieve high-efficiency MXenes-based catalysts. The electronic structures, optimized adsorption/desorption energies of the intermediates, and possible catalytic mechanisms resulting from various defects are disclosed based on combined experimental results and theoretical calculations. Current challenges and future opportunities for the mechanistic investigation and practical application of defective MXenesbased catalysts are proposed. This report aims to reveal the nature of defective MXenes electrocatalysts and to provide valuable guidelines for designing defective MXenes-based nanoarchitectures for various catalytic reactions.

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Section: Atomic Vacancymentioning

confidence: 99%

MXene Nanoarchitectonics: Defect‐Engineered 2D MXenes towards Enhanced Electrochemical Water Splitting

Tang

Yang

et al. 2022

Advanced Energy Materials

167

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“…By annealing the d‐Mo 4/3 CT x paper in argon, a volumetric capacitance of 1635 F cm −3 at 2 mV s −1 , 42% higher than the as‐prepared d‐Mo 4/3 CT x paper, was obtained. The Mo 4/3 C derived from rare‐earth‐containing i‐MAX phase (Mo 2/3 R 1/3 ) 2 AlC ( R =Gd, Tb, Dy, Ho, Er, and Y) exhibited the potential to be used as supercapacitor electrodes [33] . With increased −O functional groups onto the surface, the electrode exhibited a capacitance of 431 Fg −1 , which is the highest among all the reported Mo 4/3 C MXenes.…”

Section: Supercapacitorsmentioning

confidence: 99%

Ordered Double Transition Metal MXenes

et al. 2022

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Since the discovery of MXenes, research has progressed tremendously to explore MXenes with new compositions apart from the conventional Ti3C2Tx. Recently, the MXene family further expanded with the discovery of ordered double transition metal MXenes, wherein the metal sites are occupied by two different transition metals, which can be arranged in‐plane or out‐of‐plane forming i‐MXenes or o‐MXenes, respectively. The feature of optimizing the properties of ordered double transition metal MXenes by precise engineering of the composition, number of metal layers, interlayer spacing, and surface functionalities is distinctive among the existing 2D materials. This review provides a brief overview of the theoretical and experimental studies on the ordered double transition metal MXenes to elucidate its structure and properties. In addition, the recent trends in the synthesis and the effects of fine‐tuning the composition, structure, and functional groups on their electrochemical performance are elaborated. The current challenges faced by these emerging MXenes and future research directions are also proposed.

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“…MXene, which combines a hydrophilic surface and metal conductivity, is also a novel and promising energy materials [277,278] . For RE/MXene, Cui and co‐workers found that Mo 1.33 C MXene derived from R‐contained (Mo, R) 2 AlC (R=Gd, Tb, Dy, Ho, Er, and Y) i ‐MAX phases was treated with hydrazine monohydrate, the content of critical O groups increased, the capacitive performance was greatly improved [279] . And after series modification of RE elements and treatment of hydrazine monohydrate, the electrode denoted as Mo 1.33 C/Y‐HM can achieve a maximum specific capacitance of 431 F g −1 , which is almost 2.5 times that of the Mo 1.33 C. Coincidentally, Tao et al.…”

Section: Re Compounds and Nanocomposites For Scs Applicationmentioning

confidence: 99%

“…[277,278] For RE/MXene, Cui and co-workers found that Mo 1.33 C MXene derived from R-contained (Mo, R) 2 AlC (R=Gd, Tb, Dy, Ho, Er, and Y) i-MAX phases was treated with hydrazine monohydrate, the content of critical O groups increased, the capacitive performance was greatly improved. [279] And after series modification of RE elements and treatment of hydrazine monohydrate, the electrode denoted as Mo 3 Sc 1/3 ) 2 AlC in the plane. [280] At 2 mV s À 1 , the as-prepared electrode with a thickness of 3 μm and high density obtained a high volumetric specific capacitance of 1153 F cm À 3 (339 F g À 1 ) in 1 m H 2 SO 4 .…”

Section: Re/mxenementioning

confidence: 99%

Rare Earth‐Based Nanomaterials for Supercapacitors: Preparation, Structure Engineering and Application

Zhou

2022

ChemSusChem

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Supercapacitors (SCs) can effectively alleviate problems such as energy shortage and serious greenhouse effect. The properties of electrode materials directly affect the performance of SCs. Rare earth (RE) is known as “modern industrial vitamins”, and their functional materials have been listed as key strategic materials. In the past few years, the number of scientific reports on RE‐based nanomaterials for SCs has increased rapidly, confirming that adding RE elements or compounds to the host electrode materials with various nanostructured morphologies can greatly enhance their electrochemical performance. Although RE‐based nanomaterials have made rapid progress in SCs, there are very few works providing a comprehensive survey of this field. In view of this, a comprehensive overview of RE‐based nanomaterials for SCs is provided here, including the preparation methods, nanostructure engineering, compounds, and composites, along with their capacitance performances. The structure–activity relationships are discussed and highlighted. Meanwhile, the future challenges and perspectives are also pointed out. This Review can not only provide guidance for the further development of SCs but also arouse great interest in RE‐based nanomaterials in other research fields such as electrocatalysis, photovoltaic cells, and lithium batteries.

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Structural, magnetic properties of in-plane chemically ordered (Mo2/3R)2AlC (R = Gd, Tb, Dy, Ho, Er and Y) MAX phase and enhanced capacitance of Mo1.33C MXene derivatives

Cited by 25 publications

References 33 publications

MXene Nanoarchitectonics: Defect‐Engineered 2D MXenes towards Enhanced Electrochemical Water Splitting

MXene Nanoarchitectonics: Defect‐Engineered 2D MXenes towards Enhanced Electrochemical Water Splitting

Ordered Double Transition Metal MXenes

Rare Earth‐Based Nanomaterials for Supercapacitors: Preparation, Structure Engineering and Application

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