CN-118306995-B - Preparation method of molybdenum rare earth niobium aluminum carbide and two-dimensional derivative molybdenum niobium carbide

CN118306995BCN 118306995 BCN118306995 BCN 118306995BCN-118306995-B

Abstract

The invention belongs to the technical field of nano energy storage material preparation, and discloses a molybdenum rare earth niobium aluminum carbide and a preparation method of two-dimensional derivative molybdenum niobium carbide. The chemical formula is Mo 3.33‑x R 0.67 Nb x AlC 3 , x is more than or equal to 1 and less than or equal to 2.5, R is Sc, Y or lanthanoid, the metal carbide layer and the Al atomic layers are alternately stacked along a c-axis, one metal carbide layer is arranged between every two adjacent Al atomic layers, the metal carbide layer comprises four transition metal layers, mo atoms and R atoms preferentially occupy an outer metal carbide layer, nb atoms preferentially occupy an inner metal carbide layer, the Mo atoms and the R atoms are orderly arranged according to a 2:1 number ratio, R atoms occupy the hexagonal center formed by the Mo atoms, a layered structure with Mo atoms and the R atoms orderly arranged in a plane and Mo atoms and Nb atoms orderly arranged outside the plane is formed, and the two-dimensional derivative molybdenum-niobium carbide has excellent capacitance performance due to the existence of orderly vacancies.

Inventors

CUI WEIBIN
GUO HONGYUN
ZHONG HE
CHEN ZHAOHUI

Assignees

东北大学

Dates

Publication Date: 20260512
Application Date: 20240508

Claims (4)

1. The molybdenum rare earth niobium aluminum carbide is composed of molybdenum Mo, rare earth elements R, niobium Nb, aluminum Al and carbon C, and has an orthorhombic crystal structure, wherein the chemical formula of the molybdenum rare earth niobium aluminum carbide is Mo 3.33-x R 0.67 Nb x AlC 3 , x is more than or equal to 1 and less than or equal to 2.5, R is Sc, Y or lanthanoid, the molybdenum rare earth niobium aluminum carbide is formed by alternately stacking metal carbide layers and Al atomic layers along a C axis, one metal carbide layer is arranged between every two adjacent Al atomic layers, the metal carbide layers comprise four transition metal layers, mo atoms and R atoms preferentially occupy the outer layer of the metal carbide layers, nb atoms preferentially occupy the inner layer of the metal carbide layers, the Mo atoms and the R atoms are orderly arranged according to the number ratio of 2:1, and the R atoms occupy hexagonal centers formed by the Mo atoms, so that a layered structure with orderly Mo atoms and R atoms in plane and orderly outside the plane of the Mo atoms and Nb atoms is formed.
2. The molybdenum rare earth niobium aluminum carbide as claimed in claim 1, wherein x = 2.
3. The method for preparing the molybdenum rare earth niobium aluminum carbide according to claim 1 or 2, which is characterized in that according to the proportion of Mo to R to Nb to Al to C= (3.33-x) to 0.67 to x to 1.2 to 2.7, uniformly mixing, cold pressing into tablets, heating at a heating rate of 5-20 ℃ per minute, vacuum preserving at 1300-1600 ℃ for 0.5-10 hours, and naturally cooling to room temperature to obtain the molybdenum rare earth niobium aluminum carbide.
4. A method for preparing two-dimensional derivative molybdenum-niobium carbide according to claim 1 or 2, which is characterized in that the molybdenum-rare earth-niobium-aluminum carbide is etched by a fluorine-containing ion solution to form a two-dimensional derivative with non-stoichiometric ratio, the two-dimensional derivative contains corresponding vacancies formed by etching of orderly occupied rare earth atoms, negative ion functional groups are bonded to the surface of the two-dimensional derivative in the etching process, and the two-dimensional derivative is subjected to intercalation treatment by an intercalator to obtain a molybdenum-niobium carbide nanosheet suspension with more than a monolayer, and the two-dimensional derivative molybdenum-niobium carbide powder is obtained after freeze drying.

Description

Preparation method of molybdenum rare earth niobium aluminum carbide and two-dimensional derivative molybdenum niobium carbide Technical Field The invention relates to the technical field of nano energy storage material preparation, in particular to a preparation method of molybdenum rare earth niobium aluminum carbide and two-dimensional derivative molybdenum niobium carbide. Background The environmental problems are increasingly exacerbated by the excessive use of fossil fuels, resulting in an urgent need for clean, renewable energy sources. Wherein the design and development of energy storage devices is critical for storing new energy sources. The most widely used energy storage technology in commerce today is lithium ion batteries and supercapacitors. Due to the problems of the service life, the charging and power generating speed and the like of the traditional fuel cell and the lithium ion battery, the research of the energy storage equipment in the field of super capacitors in recent years is gradually inclined. Two-dimensional materials represented by graphene are widely used in the field of energy storage. In recent years, a new two-dimensional transition metal carbonitride (MXene) has emerged, which is prepared from its precursor MAX phase material by chemical etching. In 2011, the aluminum atomic layer in the Ti 3AlC2 MAX phase is successfully etched by using an HF aqueous solution for the first time, so that an accordion-shaped multilayer MXene."M.Naguib,M.Kurtoglu,V.Presser,J.Lu,J.Niu,M.Heon,L.Hultman,Y.Gogotsi,M.W.Barsoum,Adv.Mater.2011,23,4248." is obtained, and the MXene with more than one layer can be obtained through further intercalation. The two-dimensional MXene has great application potential in the fields of energy storage, electromagnetic shielding, electrocatalysis and the like due to the advantages of metal conductivity, abundant surface functional groups (-F, -OH, =O and the like), satisfactory hydrophilicity, exposed electronegativity and the like. Within the MAX phase family, there are two types of MAX (o-MAX and i-MAX) that are ordered into placements. The chemical formula of o-MAX is (M ', M') n+1AlCn (n=2 or 3), M 'atoms occupy the outer layer of the transition metal carbide preferentially, M' atoms occupy the inner layer of the transition metal carbide, and M 'atoms are distributed in an out-of-plane order, and the chemical formula of i-MAX is (M' 2/3,M"1/3)2 AlC, the number ratio of M 'atoms to M' atoms is 2:1 order. Disclosure of Invention The invention provides a preparation method of molybdenum rare earth niobium aluminum carbide (s-MAX) and two-dimensional derivative molybdenum niobium carbide (s-MXene), and the series of two-dimensional derivatives have excellent capacitance performance. The technical scheme of the invention is that the molybdenum rare earth niobium aluminum carbide consists of molybdenum Mo, rare earth elements R, niobium Nb, aluminum Al and carbon C, has an orthorhombic crystal structure, and has a chemical formula of Mo 3.33-xR0.67NbxAlC3, wherein x is more than or equal to 1 and less than or equal to 2.5, and R is Sc, Y or lanthanoid. The molybdenum rare earth niobium aluminum carbide is formed by alternately stacking metal carbide layers and Al atom layers along a c-axis, wherein one metal carbide layer is arranged between every two adjacent Al atom layers, the metal carbide layers comprise four transition metal layers, mo atoms and R atoms preferentially occupy the outer layers of the metal carbide layers, nb atoms preferentially occupy the inner layers of the metal carbide layers, the Mo atoms and the R atoms are orderly arranged according to the number ratio of 2:1, and the R atoms occupy the hexagonal center formed by the Mo atoms, so that a layered structure with ordered Mo atoms and R atoms in the plane and ordered Mo atoms and Nb atoms out of the plane is formed. The x=2. The preparation method of the molybdenum rare earth niobium aluminum carbide comprises the steps of uniformly mixing Mo, R, nb, al and C= (3.33-x) 0.67, x, 1.2, 2.7, cold pressing into tablets, heating at a temperature rising rate of 5-20 ℃ per minute, vacuum preserving at 1300-1600 ℃ for 0.5-10 hours, and naturally cooling to room temperature to obtain the molybdenum rare earth niobium aluminum carbide. A method for preparing two-dimensional derivative molybdenum-niobium carbide from molybdenum-rare earth-niobium-aluminum carbide comprises the steps of etching the molybdenum-rare earth-niobium-aluminum carbide through a fluorine-containing ion solution to form a two-dimensional derivative with a non-stoichiometric ratio, wherein the two-dimensional derivative comprises corresponding vacancies formed by etching of orderly occupied rare earth atoms, negative ion functional groups are bonded to the surface of the two-dimensional derivative in the etching process, the intercalation agent intercalation treatment is carried out to obtain a molybdenum-niobium carbide nanosheet s