Rodrigo M. Ronchi, Ningjun Chen, Joseph Halim, Per O. Å. Persson, Johanna Rosen
{"title":"Mo2-xCTz MXenes前驱体合金化缺陷工程及其对电化学性能的影响","authors":"Rodrigo M. Ronchi, Ningjun Chen, Joseph Halim, Per O. Å. Persson, Johanna Rosen","doi":"10.1021/acs.chemmater.5c00143","DOIUrl":null,"url":null,"abstract":"Defect engineering in the form of the intentional creation of defects has been shown to enhance the properties of two-dimensional materials in various applications. Herein, we systematically explore a simple and reproducible method for introducing random vacancies and pores in Mo-based MXenes by combining first-principles calculations and experiments. The process is based on alloying Mo<sub>2</sub>Ga<sub>2</sub>C with Cr, which is an element that, together with Ga, is selectively etched in hydrofluoric acid, resulting in vacancies and vacancy clusters in the MXene sheets. The limit of Cr incorporation on the metal site was found to be approximately 60 atom % in the precursor powder Mo<sub>2–<i>x</i></sub>Cr<sub><i>x</i></sub>C. Lower concentrations, up to 25 atom %, were used in the subsequent synthesis of Mo<sub>2–<i>x</i></sub>Cr<sub><i>x</i></sub>Ga<sub>2</sub>C, since an increasing Cr content promoted the formation of another MAX phase (Mo<sub>2–<i>x</i></sub>Cr<sub><i>x</i></sub>GaC). A Mo<sub>1.87</sub>CT<i><sub>z</sub></i> MXene derived from Mo<sub>1.87</sub>Cr<sub>0.13</sub>Ga<sub>2</sub>C (6.5 atom % Cr) exhibited excellent electrochemical behavior, reaching a volumetric capacitance of 1117 Fcm<sup>–3</sup> at 2 mVs<sup>–1</sup> scan rate, and suggested that defect concentration can be used to tune the rate capability. Overall, we have demonstrated that using Cr as a sacrificial element in the MAX phase is a simple and effective strategy for the defect engineering of MXenes. Moreover, this method can likely be extended to include other sacrificial elements and MAX phases, making MXene defect engineering a viable pathway for property enhancement across various applications, including energy storage and catalysis.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"250 1","pages":""},"PeriodicalIF":7.0000,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Defect Engineering of Mo2–xCTz MXenes through Precursor Alloying and Effects on Electrochemical Properties\",\"authors\":\"Rodrigo M. Ronchi, Ningjun Chen, Joseph Halim, Per O. Å. Persson, Johanna Rosen\",\"doi\":\"10.1021/acs.chemmater.5c00143\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Defect engineering in the form of the intentional creation of defects has been shown to enhance the properties of two-dimensional materials in various applications. Herein, we systematically explore a simple and reproducible method for introducing random vacancies and pores in Mo-based MXenes by combining first-principles calculations and experiments. The process is based on alloying Mo<sub>2</sub>Ga<sub>2</sub>C with Cr, which is an element that, together with Ga, is selectively etched in hydrofluoric acid, resulting in vacancies and vacancy clusters in the MXene sheets. The limit of Cr incorporation on the metal site was found to be approximately 60 atom % in the precursor powder Mo<sub>2–<i>x</i></sub>Cr<sub><i>x</i></sub>C. Lower concentrations, up to 25 atom %, were used in the subsequent synthesis of Mo<sub>2–<i>x</i></sub>Cr<sub><i>x</i></sub>Ga<sub>2</sub>C, since an increasing Cr content promoted the formation of another MAX phase (Mo<sub>2–<i>x</i></sub>Cr<sub><i>x</i></sub>GaC). A Mo<sub>1.87</sub>CT<i><sub>z</sub></i> MXene derived from Mo<sub>1.87</sub>Cr<sub>0.13</sub>Ga<sub>2</sub>C (6.5 atom % Cr) exhibited excellent electrochemical behavior, reaching a volumetric capacitance of 1117 Fcm<sup>–3</sup> at 2 mVs<sup>–1</sup> scan rate, and suggested that defect concentration can be used to tune the rate capability. Overall, we have demonstrated that using Cr as a sacrificial element in the MAX phase is a simple and effective strategy for the defect engineering of MXenes. 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Defect Engineering of Mo2–xCTz MXenes through Precursor Alloying and Effects on Electrochemical Properties
Defect engineering in the form of the intentional creation of defects has been shown to enhance the properties of two-dimensional materials in various applications. Herein, we systematically explore a simple and reproducible method for introducing random vacancies and pores in Mo-based MXenes by combining first-principles calculations and experiments. The process is based on alloying Mo2Ga2C with Cr, which is an element that, together with Ga, is selectively etched in hydrofluoric acid, resulting in vacancies and vacancy clusters in the MXene sheets. The limit of Cr incorporation on the metal site was found to be approximately 60 atom % in the precursor powder Mo2–xCrxC. Lower concentrations, up to 25 atom %, were used in the subsequent synthesis of Mo2–xCrxGa2C, since an increasing Cr content promoted the formation of another MAX phase (Mo2–xCrxGaC). A Mo1.87CTz MXene derived from Mo1.87Cr0.13Ga2C (6.5 atom % Cr) exhibited excellent electrochemical behavior, reaching a volumetric capacitance of 1117 Fcm–3 at 2 mVs–1 scan rate, and suggested that defect concentration can be used to tune the rate capability. Overall, we have demonstrated that using Cr as a sacrificial element in the MAX phase is a simple and effective strategy for the defect engineering of MXenes. Moreover, this method can likely be extended to include other sacrificial elements and MAX phases, making MXene defect engineering a viable pathway for property enhancement across various applications, including energy storage and catalysis.
期刊介绍:
The journal Chemistry of Materials focuses on publishing original research at the intersection of materials science and chemistry. The studies published in the journal involve chemistry as a prominent component and explore topics such as the design, synthesis, characterization, processing, understanding, and application of functional or potentially functional materials. The journal covers various areas of interest, including inorganic and organic solid-state chemistry, nanomaterials, biomaterials, thin films and polymers, and composite/hybrid materials. The journal particularly seeks papers that highlight the creation or development of innovative materials with novel optical, electrical, magnetic, catalytic, or mechanical properties. It is essential that manuscripts on these topics have a primary focus on the chemistry of materials and represent a significant advancement compared to prior research. Before external reviews are sought, submitted manuscripts undergo a review process by a minimum of two editors to ensure their appropriateness for the journal and the presence of sufficient evidence of a significant advance that will be of broad interest to the materials chemistry community.