Abstract: An object of the present disclosure is to provide a thin-film-like composite of nanocrystal, as a nanocrystalline material having excellent handling properties, which can overcome the above-mentioned problems of a nanocrystalline material having a powdery form while satisfactorily maintaining the properties of the nanocrystalline material (e.g., excellent catalytic activity). A thin-film-like composite of nanocrystal, characterized in that the thin-film-like composite of nanocrystal includes a thin-film-like connected assembly in which a plurality of nanocrystalline pieces each having a flake-like form and having a main surface and an end surface are connected to each other, the main surfaces of the plurality of nanocrystalline pieces exposed to the outside of the connected assembly are arranged so as to form gaps therebetween, and the connected assembly has a plan view area of 1 mm2 or more.

Abstract: The present disclosure relates to a method for producing metal oxide nanoparticles includes a first step of preparing a reaction solution containing a metal complex, an alcohol, and water; a second step of heating the reaction solution for phase-separation under a hermetically sealed atmosphere where the volumetric expansion ratio of the reaction solution reaches 5 to 15%; a third step of holding the reaction solution heated in the second step for 30 minutes or more for dehydrating the metal complex to precipitate the metal oxide nanoparticles; and a fourth step of collecting the metal oxide nanoparticles after the metal oxide nanoparticles are cooled.

Abstract: The present disclosure relates to a nanocrystal composite includes a connected aggregate including a plurality of nanocrystal fragments connected to one another, each nanocrystal fragment having a main surface and an end surface, and nanoparticles supported on the connected aggregate. The plurality of nanocrystal fragments each have a flaky shape; the plurality of nanocrystal fragments have gaps between the main surfaces; and the gaps G are arranged so as to open to the outside of the connected aggregate. The nanoparticles have a metallic element different from that of the plurality of nanocrystal fragments; and a proportion of a visual field area of the nanoparticles with respect to a visual field area of the plurality of nanocrystal fragments is 2% or more and 50% or less.

Abstract: A crystal-orientation controlled complex comprising a connected assembly having a thin film shape, in which a plurality of crystal pieces are connected with each other, the crystal pieces having a flake shape and having a main surface and an end surface, wherein the main surface has a crystal orientation relative to a specific crystal plane, and the thin film shaped connected assembly has a polarization singularity.

Abstract: A catalyst includes: a base material; and a nanocrystalline metal oxide composite having a plurality of accumulated flake-like nanocrystalline pieces in a connected state on the surface of the base material, the flake-like nanocrystalline pieces containing a metal oxide to accumulate, wherein the nanocrystalline metal oxide composite is configured such that an end surface of at least one of the nanocrystalline pieces is connected; the nanocrystalline pieces include a plurality of stacked surfaces stacked in a direction in which a main surface becomes an uppermost stacked surface; and when metal atoms or oxygen atoms forming the metal oxide are regarded as main constituent atoms, a proportion by number of the main constituent atoms to the metal atoms and the oxygen atoms forming the metal oxide existing on each stacked surface is 80% or more, and the main constituent atoms have a specific crystal orientation which changes in each stack.

Abstract: The present disclosure relates to a method for producing metal oxide nanoparticles includes a first step of preparing a reaction solution containing a metal complex, an alcohol, and water; a second step of heating the reaction solution for phase-separation under a hermetically sealed atmosphere where the volumetric expansion ratio of the reaction solution reaches 5 to 15%; a third step of holding the reaction solution heated in the second step for 30 minutes or more for dehydrating the metal complex to precipitate the metal oxide nanoparticles; and a fourth step of collecting the metal oxide nanoparticles after the metal oxide nanoparticles are cooled.

Abstract: The present disclosure provides that a catalyst exhibits excellent catalytic activity in both a hydrogenation involving a hydrogen-storing body containing an aromatic compound, and a dehydrogenation involving a hydrogen-supplying body containing a hydrogen derivative of the aromatic compound, wherein the catalyst contains a nanocrystalline composite having two or more accumulated flake-like nanocrystalline pieces in a connected state, the flake-like nanocrystalline pieces each having a main surface and an end surface, and in that the nanocrystalline composite is configured such that, when two adjacent nanocrystalline pieces are viewed, an end surface of at least one of the nanocrystalline pieces is connected.

Abstract: An object of the present disclosure is to provide a thin-film-like composite of nanocrystal, as a nanocrystalline material having excellent handling properties, which can overcome the above-mentioned problems of a nanocrystalline material having a powdery form while satisfactorily maintaining the properties of the nanocrystalline material (e.g., excellent catalytic activity). A thin-film-like composite of nanocrystal, characterized in that the thin-film-like composite of nanocrystal includes a thin-film-like connected assembly in which a plurality of nanocrystalline pieces each having a flake-like form and having a main surface and an end surface are connected to each other, the main surfaces of the plurality of nanocrystalline pieces exposed to the outside of the connected assembly are arranged so as to form gaps therebetween, and the connected assembly has a plan view area of 1 mm2 or more.

Abstract: A catalyst includes: a base material; and a nanocrystalline metal oxide composite having a plurality of accumulated flake-like nanocrystalline pieces in a connected state on the surface of the base material, the flake-like nanocrystalline pieces containing a metal oxide to accumulate, wherein the nanocrystalline metal oxide composite is configured such that an end surface of at least one of the nanocrystalline pieces is connected; the nanocrystalline pieces include a plurality of stacked surfaces stacked in a direction in which a main surface becomes an uppermost stacked surface; and when metal atoms or oxygen atoms forming the metal oxide are regarded as main constituent atoms, a proportion by number of the main constituent atoms to the metal atoms and the oxygen atoms forming the metal oxide existing on each stacked surface is 80% or more, and the main constituent atoms have a specific crystal orientation which changes in each stack.

Abstract: The present disclosure provides that a catalyst exhibits excellent catalytic activity in both a hydrogenation involving a hydrogen-storing body containing an aromatic compound, and a dehydrogenation involving a hydrogen-supplying body containing a hydrogen derivative of the aromatic compound, wherein the catalyst contains a nanocrystalline composite having two or more accumulated flake-like nanocrystalline pieces in a connected state, the flake-like nanocrystalline pieces each having a main surface and an end surface, and in that the nanocrystalline composite is configured such that, when two adjacent nanocrystalline pieces are viewed, an end surface of at least one of the nanocrystalline pieces is connected.