A photocatalyst/alloy fine-particle dispersion containing two kinds of fine particles dispersed in an aqueous dispersion medium, (i) photocatalyst fine particles and (ii) alloy fine particles containing an antibacterial/antifungal metal, easily forms a photocatalyst/alloy fine-particle thin film of high transparency that exhibits antibacterial/antifungal properties regardless of the presence or absence of light irradiation.

The problem of the present invention is to provide an exhaust gas purification catalyst which can exhibit sufficient purification performance under a high Ga condition while having a resistance to stress such as high-temperature and poisonous substances. The present invention relates to an exhaust gas purification catalyst comprising two or more catalyst coating layers on a substrate, wherein a lower catalyst coating layer that is present lower with respect to an uppermost catalyst coating layer has a structure where a large number of voids are included and high-aspect-ratio pores having an aspect ratio of 5 or more account for a certain proportion or more of the whole volume of voids, thereby to improve gas diffusivity in the lower catalyst coating layer.

The problem of the present invention is to provide an exhaust gas purification catalyst which can exhibit sufficient purification performance under a high Ga condition while having a resistance to stress such as high-temperature and poisonous substances. The present invention relates to an exhaust gas purification catalyst comprising two or more catalyst coating layers on a substrate, wherein a lower catalyst coating layer that is present lower with respect to an uppermost catalyst coating layer has a structure where a large number of voids are included and high-aspect-ratio pores having an aspect ratio of 5 or more account for a certain proportion or more of the whole volume of voids, thereby to improve gas diffusivity in the lower catalyst coating layer.

The present invention provides titania particles which are formed by providing a titania sol and spray drying the titania sol. A morphology of the dried titania particles is controlled by producing the titania sol from a TiO.sub.2 containing slurry and controlling the pH of the slurry to be 3 pH units or more from the iso-electric point of the titania by adding a peptizing agent to reduce an extent to which the titania sol is flocculated, or by producing the titania sol from a TiO.sub.2 containing slurry and adjusting the iso-electric point to be 3 pH units or more from the pH of the slurry by adding a dispersant to reduce an extent to which the titania sol is flocculated. The titania particles have a continuous exterior convex surface, a diameter of 30 m or less, a BET specific surface area of 50 m.sup.2/g or more, and are porous.

The present invention provides titania particles which are formed by providing a titania sol and spray drying the titania sol. A morphology of the dried titania particles is controlled by producing the titania sol from a TiO.sub.2 containing slurry and controlling the pH of the slurry to be 3 pH units or more from the iso-electric point of the titania by adding a peptizing agent to reduce an extent to which the titania sol is flocculated, or by producing the titania sol from a TiO.sub.2 containing slurry and adjusting the iso-electric point to be 3 pH units or more from the pH of the slurry by adding a dispersant to reduce an extent to which the titania sol is flocculated. The titania particles have a continuous exterior convex surface, a diameter of 30 m or less, a BET specific surface area of 50 m.sup.2/g or more, and are porous.

An exhaust gas-purifying catalyst of the present invention comprising a substrate, a first catalyst layer comprising a first supported catalyst, a second supported catalyst, palladium, and a first nitrogen oxide storage material, and a second catalyst layer comprising a third supported catalyst having an alloying rate of platinum and palladium of 40% or more and a second nitrogen oxide storage material, wherein a mass of the second supported catalyst is greater than a mass of the first supported catalyst and greater than a mass of the third supported catalyst.

An exhaust gas-purifying catalyst of the present invention comprising a substrate, a first catalyst layer comprising a first supported catalyst, a second supported catalyst, palladium, and a first nitrogen oxide storage material, and a second catalyst layer comprising a third supported catalyst having an alloying rate of platinum and palladium of 40% or more and a second nitrogen oxide storage material, wherein a mass of the second supported catalyst is greater than a mass of the first supported catalyst and greater than a mass of the third supported catalyst.

A method of coating an end surface of a monolithic substrate with a liquid is described and an apparatus therefor. The method comprises: (a) conveying a monolithic substrate to or toward a coating roller; and (b) applying a liquid onto an end surface of the monolithic substrate by contacting the end surface with the coating roller loaded with the liquid.

A method of coating an end surface of a monolithic substrate with a liquid is described and an apparatus therefor. The method comprises: (a) conveying a monolithic substrate to or toward a coating roller; and (b) applying a liquid onto an end surface of the monolithic substrate by contacting the end surface with the coating roller loaded with the liquid.

Shaped porous carbon products and processes for preparing these products are provided. The shaped porous carbon products can be used, for example, as catalyst supports and adsorbents. Catalyst compositions including these shaped porous carbon products, processes of preparing the catalyst compositions, and various processes of using the shaped porous carbon products and catalyst compositions are also provided.