Provided are novel transition metal dichalcogenides having a platelet structure and comprising a 2H phase region and/or a 3R phase region. The platelets exhibit a narrow size distribution and comparatively high surface area and edge area, which characteristics render the platelets especially suitable for catalysis applications, as well as use in electronic devices. Also provided are methods of synthesizing the disclosed transition metal dichalcogenide platelets.

Processes for forming Mo and W containing thin films, such as MoS.sub.2, WS.sub.2, MoSe.sub.2, and WSe.sub.2 thin films are provided. Methods are also provided for synthesizing Mo or W beta-diketonate precursors. Additionally, methods are provided for forming 2D materials containing Mo or W.

A method of making an atomic layer nanoribbon that includes forming a double atomic layer ribbon having a first monolayer and a second monolayer on a surface of the first monolayer, wherein the first monolayer and the second monolayer each contains a transition metal dichalcogenide material, oxidizing at least a portion of the first monolayer to provide an oxidized portion, and removing the oxidized portion to provide an atomic layer nanoribbon of the transition metal dichalcogenide material. Also provided are double atomic layer ribbons, double atomic layer nanoribbons, and single atomic layer nanoribbons prepared according to the method.

A method of making an atomic layer nanoribbon that includes forming a double atomic layer ribbon having a first monolayer and a second monolayer on a surface of the first monolayer, wherein the first monolayer and the second monolayer each contains a transition metal dichalcogenide material, oxidizing at least a portion of the first monolayer to provide an oxidized portion, and removing the oxidized portion to provide an atomic layer nanoribbon of the transition metal dichalcogenide material. Also provided are double atomic layer ribbons, double atomic layer nanoribbons, and single atomic layer nanoribbons prepared according to the method.

A process for preparing stacks of metal chalcogenide flakes includes: (a) reacting together a source of the metal atom of the target metal chalcogenide with a source of the chalcogenide atom of the target metal chalcogenide, in the presence of a spacer, so as to produce flakes of the metal chalcogenide; (b) depositing metal chalcogenide flakes obtained using step (a) onto a substrate to form a stack of assembled metal chalcogenide flakes, wherein the spacer contains an alkyl chain linked to a functional group able to bond to the metal chalcogenide surface, said alkyl chain having a length of less than 18 carbon atoms, preferably between 6 and 14 carbon atoms.

Provided is a molybdenum sulfide that is ribbon-shaped and particularly suitable for a hydrogen generation catalyst. Disclosed are a ribbon-shaped molybdenum sulfide, in which 50 particles as measured by observation with a scanning electron microscope (SEM) have a shape of, on average, 500 to 10000 nm in length, 10 to 1000 nm in width, and 3 to 200 nm in thickness; a method for producing the ribbon-shaped molybdenum sulfide, including: (1) heating a molybdenum oxide at a temperature of 200 to 1000° C. in the presence of a sulfur source; or (2) heating a molybdenum oxide at a temperature of 100 to 800° C. in the absence of a sulfur source, and then heating the molybdenum oxide at a temperature of 200 to 1000° C. in the presence of a sulfur source; and a hydrogen generation catalyst including the ribbon-shaped molybdenum sulfide.

Provided is a molybdenum sulfide that is ribbon-shaped and particularly suitable for a hydrogen generation catalyst. Disclosed are a ribbon-shaped molybdenum sulfide, in which 50 particles as measured by observation with a scanning electron microscope (SEM) have a shape of, on average, 500 to 10000 nm in length, 10 to 1000 nm in width, and 3 to 200 nm in thickness; a method for producing the ribbon-shaped molybdenum sulfide, including: (1) heating a molybdenum oxide at a temperature of 200 to 1000° C. in the presence of a sulfur source; or (2) heating a molybdenum oxide at a temperature of 100 to 800° C. in the absence of a sulfur source, and then heating the molybdenum oxide at a temperature of 200 to 1000° C. in the presence of a sulfur source; and a hydrogen generation catalyst including the ribbon-shaped molybdenum sulfide.

The disclosure relates to an electronic beam machining system. The system includes a vacuum chamber; an electron gun located in the vacuum chamber and used to emit electron beam; a holder located in the vacuum chamber and used to fix an object; a control computer; and a diffraction unit located in the vacuum chamber; the diffraction unit includes a two-dimensional nanomaterial; the electron beam transmits the two-dimensional nanomaterial to form a transmission electron beam and a plurality of diffraction electron beams; the transmission electron beam and the plurality of diffraction electron beams radiate the object to form a transmission spot and a plurality of diffraction spots.

The disclosure relates to an electronic beam machining system. The system includes a vacuum chamber; an electron gun located in the vacuum chamber and used to emit electron beam; a holder located in the vacuum chamber and used to fix an object; a control computer; and a diffraction unit located in the vacuum chamber; the diffraction unit includes a two-dimensional nanomaterial; the electron beam transmits the two-dimensional nanomaterial to form a transmission electron beam and a plurality of diffraction electron beams; the transmission electron beam and the plurality of diffraction electron beams radiate the object to form a transmission spot and a plurality of diffraction spots.

Methods for the scalable and systematic synthesis of semiconducting Chevrel phase compounds via self-propagating high temperature synthesis (SHS) are provided. The provided methods utilize elemental precursors not utilized by typical synthesis methods. The precursors may include molybdenum (Mo), molybdenum disulfide (MoS.sub.2), and a ternary cation. In various aspects, the ternary cation may be copper (Cu), iron (Fe), or nickel (Ni). The utilization of the provided precursors and SHS decreases the time it takes to synthesize Chevrel phase compounds as compared to typical heat treatment methods.