# US 2020/0399771 A1 · Method for hf-free facile and rapid synthesis of mxenes related compounds > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0399771 A1 - Document ID: US20200399771A1 - Status: Published application - Kind: A1 - Application number: 16/946,459 - Filed: 2020-06-23 - Published: 2020-12-24 - Earliest claimed: 2019-06-24 - Assignees: The Hong Kong Polytechnic University - Applicants: The Hong Kong Polytechnic University - Inventors: Jianhua HAO; Sin Yi PANG - Web page: https://patentgrep.com/patent/US20200399771A1 ## CPC - C25B 11/069: consisting of at least one single element and at least one compound; consisting of two or more compounds - C01B 32/914: Carbides of single elements - C01B 32/921: Titanium carbide - C25B 1/00: Electrolytic production of inorganic compounds or non-metals - C25B 1/01: Products - C25B 11/046: Alloys - C25B 11/051: Electrodes formed of electrocatalysts on a substrate or carrier - C25F 5/00: Electrolytic stripping of metallic layers or coatings - C01B 21/0617: {with vanadium, niobium or tantalum} - C01B 21/076: with titanium or zirconium {or hafnium} - C01P 2004/20: extending in two dimensions, e.g. plate-like - C25B: ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR (anodic or cathodic protection C23F13/00; single-crystal growth C30B) - C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C} - C25F: PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR - C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS ## Abstract Provided herein is a method for preparing MXenes, such as Ti2CTx, Cr2CTx, and V2CTx, products prepared therefrom, and compositions and devices including the same. ## Claims ### Claim 1 A method for preparing a MXene, the method comprising: providing a composite electrode comprising at least one MAX-phase composition and a carbonaceous material, wherein the at least one MAX-phase composition has an empirical formula of Mn+1AXn or M2M′nXn+1, wherein each of M and M′ is independently a Group IIIB, IVB, VB, or VIB metal; A is a Group IIB, IIIA, IVA, or VA element; and each X is C, N, or a combination thereof; and n is 1, 2, or 3; a counter electrode; and an electrolyte solution comprising an etchant between and in contact with the composite electrode and the counter electrode; and applying an electric current between the composite electrode and the counter electrode resulting in electrolytic reduction of the at least one MAX-phase composition thereby forming the MXene, wherein the electrolytic reduction is conducted at a temperature between 25 to 80° C. ### Claim 2 (depends on 1) The method of claim 1, wherein the electric current is applied at a voltage 2 V or less. ### Claim 3 (depends on 1) The method of claim 1, wherein the etchant is chloride. ### Claim 4 (depends on 1) The method of claim 1, wherein the carbonaceous material is carbon black (CB), carbon fiber cloth (CFC), or a mixture thereof. ### Claim 5 (depends on 1) The method of claim 1, wherein the composite electrode further comprises a binder. ### Claim 6 (depends on 1) The method of claim 1, wherein the at least one MAX-phase composition and the carbonaceous material are present in the composite electrode in a mass ratio of 80:20 to 99:1, respectively. ### Claim 7 (depends on 6) The method of claim 6, wherein the composite electrode further comprises a binder, wherein the binder is present in the composite electrode at 0.1 to 3% by weight. ### Claim 8 (depends on 1) The method of claim 1, wherein the electrolytic reduction is conducted at a temperature between 30 to 70° C. ### Claim 9 (depends on 1) The method of claim 1, wherein each of M and M′ is independently Hf, Cr, Mn, Mo, Nb, Sc Ta, Ti, V, W, or Zr; and A is Al. ### Claim 10 (depends on 8) The method of claim 8, wherein the electrolyte solution comprises 0.5 to 1.5 M HCl. ### Claim 11 (depends on 10) The method of claim 10, wherein each of M and M′ is independently Hf, Cr, Mn, Mo, Nb, Sc Ta, Ti, V, W, or Zr; and A is Al. ### Claim 12 (depends on 1) The method of claim 1, wherein the applying an electric current is maintained for 10 hours or less. ### Claim 13 (depends on 1) The method of claim 1, wherein the method comprises: providing a composite electrode comprising at least one MAX-phase composition, a carbonaceous material and a binder, wherein the at least one MAX-phase composition has an empirical formula of Mn+1AXn or M2M′nXn+1, wherein each of M and M′ is independently Hf, Cr, Mn, Mo, Nb, Sc Ta, Ti, V, W, or Zr; and A is Al; and each X is C, N, or a combination thereof; and n is 1, 2, or 3; a counter electrode; and an electrolyte solution between and in contact with the composite electrode and the counter electrode having a pH of 1 or less; and applying an electric current between the composite electrode and the counter electrode at a voltage 2 V or less resulting in the electrolytic reduction of the at least one MAX-phase composition thereby forming the MXene, wherein the electrolytic reduction is conducted at a temperature between 30 to 70° C. ### Claim 14 (depends on 12) The method of claim 12, wherein the electrolytic reduction is conducted at a temperature between 40 to 60° C. ### Claim 15 (depends on 12) The method of claim 12, wherein the electrolyte solution comprises 0.5 to 1.5 M HCl. ### Claim 16 (depends on 12) The method of claim 12, wherein the at least one MAX-phase composition and the carbonaceous material are present in the composite electrode in a mass ratio of 80:20 to 99:1, respectively and the binder is present in the composite electrode 0.1 to 2% by weight. ### Claim 17 (depends on 12) The method of claim 12, wherein each of M and M′ is independently Hf, Cr, Mn, Mo, Nb, Sc Ta, Ti, V, W, or Zr; and A is Al. ### Claim 18 (depends on 12) The method of claim 12, wherein at least one MAX-phase composition has an empirical formula of Mn+1AXn and M is Cr, Ti, and V; A is Al. ### Claim 19 A method for preparing a MXene, the method comprising: providing a composite electrode comprising at least one MAX-phase composition; a carbonaceous material selected from the group consisting of CB, CFC, and combinations thereof; a binder, wherein the at least one MAX-phase composition has an empirical formula of Mn+1AXn, wherein each of M is Cr, Ti, and V; A is Al; and each X is C or N; and n is 1, 2, or 3; wherein the at least one MAX-phase composition and carbonaceous material are present in the composite electrode in a mass ratio of 90:10 to 99:1; and wherein the binder is present in the composite electrode in a weight ratio of 1.0-1.5% by mass; a counter electrode; and an electrolyte solution comprising 0.5 to 1.5 M HCl between and in contact with the composite electrode and the counter electrode; and applying an electric current between the composite electrode and the counter electrode at a voltage 0.2 to 1.5 V for 8 to 10 hours resulting in the electrolytic reduction of the at least one MAX-phase composition thereby forming the MXene, wherein the electrolytic reduction is conducted at a temperature between 45 to 55° C. ### Claim 20 (depends on 1) A MXene formed according to the method of claim 1.