A method for preparing acrylic acid, more specifically, to a method for preparing acrylic acid under a neutral condition at high yield in a short time without using a base, unlike the prior art in which a base is essentially used. The acrylic acid is produced using a supported catalyst having a specific composition when preparing acrylic acid by oxidation of allyl alcohol. Particularly, the preparation method can recover acrylic acid rather than acrylic acid salt as a final product, and thus has an advantage that the overall process cost can be reduced by eliminating essential processes in the prior art, such as ion exchange after the acidification process required for the conversion of acrylic acid salt to acrylic acid.

A photocatalytic functional film has a structure of a substrate, a barrier layer and a photocatalytic layer stacked one on another. The barrier layer is an amorphous TiO.sub.2 film, the photocatalyst layer comprises an amorphous TiO.sub.2 film, and particles of visible light responsive photocatalytic material formed on the surface of the amorphous TiO.sub.2 film. A method for producing a photocatalytic functional film includes: adding an alcohol solvent and an acid to a titanium precursor to obtain a TiO.sub.2 amorphous sol by dehydration and de-alcoholization reaction; applying and drying the TiO.sub.2 amorphous sol on a substrate to form a barrier layer; and applying and drying a composition formed by mixing particles of visible light responsive photocatalyst material with the TiO.sub.2 amorphous sol on the barrier layer, to form a photocatalyst layer.

Described herein are heterogeneous materials comprising a p-type semiconductor comprising two metal oxide compounds of the same metal in two different oxidation states and an n-type semiconductor having a deeper valence band than the p-type semiconductor valence bands, wherein the semiconductor types are in ionic communication with each other. The heterogeneous materials enhance photocatalytic activity.

A lean NO.sub.x trap catalyst and its use in an emission treatment system for internal combustion engines is disclosed. The lean NO.sub.x trap catalyst comprises a first layer and a second layer.

A method for preparing acrylic acid, more specifically, to a method for preparing acrylic acid under a neutral condition at high yield in a short time without using a base, unlike the prior art in which a base is essentially used. The acrylic acid is produced using a supported catalyst having a specific composition when preparing acrylic acid by oxidation of allyl alcohol. Particularly, the preparation method can recover acrylic acid rather than acrylic acid salt as a final product, and thus has an advantage that the overall process cost can be reduced by eliminating essential processes in the prior art, such as ion exchange after the acidification process required for the conversion of acrylic acid salt to acrylic acid.

The invention relates to a catalyst that comprises at least the tantalum element, at least an aldolizing element and at least a mesoporous oxide matrix, with the tantalum mass being between 0.1 and 30% of the mesoporous oxide matrix mass, the mass of the at least one aldolizing element being between 0.02 and 4% of the mesoporous oxide matrix mass, and use thereof.

A mesoporous mixed oxide catalyst that comprises silicon and at least one metal M that is selected from the group that consists of the elements of groups 4 and 5 of the periodic table and mixtures thereof, with the mass of metal M being between 0.1 and 20% of the mixed oxide mass.

Provided are a titanium dioxide-coated upconverting nanoparticle (UCNP) and a photocatalyst complex containing a gold nanorod (GNR) combined with the titanium dioxide-coated UCNP.

The present invention provides a method for producing a heterojunction photocatalyst having higher catalytic activity than that of conventional heterojunction photocatalysts, and a heterojunction photocatalyst. A method for producing a heterojunction photocatalyst having a solid state mediator between a hydrogen-evolution photocatalyst and an oxygen-evolution photocatalyst, which includes the following step 1: step 1: a step of joining the solid state mediator onto the oxygen-evolution photocatalyst by at least one method selected from the group consisting of a photoelectrodeposition method, an impregnation supporting method, and a precipitation method, in each of which an organic carboxylic acid compound and a solid state mediator or a precursor of the solid state mediator are used.