Provided are enhanced MXene materials made from MAX-phase precursors that comprise an excess of metal A. The resultant enhanced MXenes exhibit improved stability over periods of days and months, particularly when stored in aqueous media.

Provided are enhanced MXene materials made from MAX-phase precursors that comprise an excess of metal A. The resultant enhanced MXenes exhibit improved stability over periods of days and months, particularly when stored in aqueous media.

Preparing MAX phase structures includes forming a gel including a transition metal M, a Group 3A or Group 4A metal or semimetal A, and an acidic chelating agent or gelling agent X. X includes one or both of carbon and nitrogen. Preparing the MAX phase structures further includes shaping the gel to yield a shaped gel and heating the shaped gel to yield carbonaceous MAX phase structures with a composition represented by M.sub.n+1AX.sub.n, wherein n is 1, 2, 3, or 4. The MAX phase structures can be thick films, microspheres, or microwires.

Preparing MAX phase structures includes forming a gel including a transition metal M, a Group 3A or Group 4A metal or semimetal A, and an acidic chelating agent or gelling agent X. X includes one or both of carbon and nitrogen. Preparing the MAX phase structures further includes shaping the gel to yield a shaped gel and heating the shaped gel to yield carbonaceous MAX phase structures with a composition represented by M.sub.n+1AX.sub.n, wherein n is 1, 2, 3, or 4. The MAX phase structures can be thick films, microspheres, or microwires.

A method according to an embodiment of the present invention is for preparing powdered composite carbide of tungsten and titanium in which tungsten trioxide (WO.sub.3), titanium dioxide (TiO.sub.2) and carbon (C), each being in powdered form are mixed with a reducing agent powder to obtain a reaction mixture in the mixing step, followed by the synthesis step in which the reaction mixture is heated at a temperature of about 600° C. to 1200° C. to obtain the reaction products, and the washing step in which the reaction products are washed with water. The method for preparing tungsten titanium carbide powder is capable of carrying out both reduction and carburizing at a relatively low temperature and affords homogeneity in shape and particle size in the resultant composite carbide.

A method according to an embodiment of the present invention is for preparing powdered composite carbide of tungsten and titanium in which tungsten trioxide (WO.sub.3), titanium dioxide (TiO.sub.2) and carbon (C), each being in powdered form are mixed with a reducing agent powder to obtain a reaction mixture in the mixing step, followed by the synthesis step in which the reaction mixture is heated at a temperature of about 600° C. to 1200° C. to obtain the reaction products, and the washing step in which the reaction products are washed with water. The method for preparing tungsten titanium carbide powder is capable of carrying out both reduction and carburizing at a relatively low temperature and affords homogeneity in shape and particle size in the resultant composite carbide.

Compositions and devices comprising MXene materials, suitable for use as selective and/or tunable infrared emitters and/or absorbers, and methods of making coatings with low thermal emissivities using coatings comprising MXene materials.

Compositions and devices comprising MXene materials, suitable for use as selective and/or tunable infrared emitters and/or absorbers, and methods of making coatings with low thermal emissivities using coatings comprising MXene materials.

An electrode or wiring, an electrode pair, and a method for manufacturing the electrode or wiring. The electrode or wiring includes: particles of a layered material including one or more layers; and metal particles or a sintered metal. The one or plural layers include a layer body represented by M.sub.mX.sub.n, wherein M is at least one metal belonging to group 3, 4, 5, 6, or 7, X is a carbon atom, a nitrogen atom, or a combination thereof, n is 1-4, and m is greater than n and at most 5, and a modification or terminal T (T being at least one of a hydroxyl group, a fluorine atom, a chlorine atom, an oxygen atom, and a hydrogen atom) is present on the surface of the layer body.

The invention relates to a method for producing a non-oxide ceramic powder comprising a nitride, a carbide, a boride or at least one MAX phase with the general composition Mn+1AXn, where M=at least one element from the group of transition elements (Sc, Ti, V, Cr, Zr, Nb, Mo, Hf and Ta), A=at least one A group element from the group (Si, Al, Ga, Ge, As, Cd, In, Sn, Tl and Pb), X=carbon (C) and/or nitrogen (N) and/or boron (B), and n=1, 2 or 3. According to the invention, corresponding quantities of elementary starting materials or other precursors are mixed with at least one metal halide salt (NZ), compressed (pellet), and heated for synthesis with a metal halide salt (NZ). The compressed pellet is first enveloped with another metal halide salt, compressed again, arranged in a salt bath and heated therewith until the melting temperature of the salt is exceeded. Optionally, melted silicate can be added, which prevents the salt from evaporating at high temperatures. Advantageously, the method can be carried out in the presence of air.