A substrate (11) of an exhaust gas purification catalyst (10) includes inflow-side cells (21), outflow-side cells (22), and porous partition walls (23), each porous partition wall separating the cells (21, 22) from each other. A first catalyst portions (14) is provided at least on a portion of a side of the partition wall (23) that faces the inflow-side cell (21), the portion being located on an upstream side in an exhaust gas flow direction, and a second catalyst portion (15) is provided at least on a portion of a side of the partition wall that faces the outflow-side cell, the portion being located on a downstream side in the exhaust gas flow direction. A first pore volume is greater than a second pore volume, where the first pore volume is a pore volume of pores with a pore size of 10 m to 18 um, as measured on the first catalyst portions (14) and the partition walls (23) within a region where the first catalyst portions (14) are provided, and the second pore volume is a pore volume of pores with a pore size of 10 m to 18 m, as measured on the second catalyst portions (15) and the partition walls (23) within a region where the second catalyst portions (15) are provided. The first catalyst portion (14) exhibits the peak top of the pore size at between 20 nm and 500 nm.

An emission control device for a vehicle, which includes an open cell carbon foam substrate having a geometric surface area of at least about 5000 m.sup.2/m.sup.3, wherein the substrate has a catalytic metal.

A substrate for a catalytic converter, comprising an open cell carbon foam having a geometric surface area of at least about 5000 m.sup.2/m.sup.3 and a permeability of at least about 8.0 darcys.

Provided are the following: a mixture of visible light-responsive photocatalytic titanium oxide fine particles which can conveniently produce a photocatalyst thin film that exhibits photocatalyst activity even with only visible light (400-800 nm) and that exhibits high transparency; a dispersion liquid of the fine particles; a method for producing the dispersion liquid; a photocatalyst thin film; and a member having the photocatalyst thin film on a surface thereof. The mixture of visible light-responsive photocatalytic titanium oxide fine particles is characterized by containing two kinds of titanium dioxide fine particles: first titanium oxide fine particles, in which a tin component and a transition metal component (excluding an iron group element component) that increases visible light response properties form a solid solution, and second titanium oxide fine particles, in which an iron group element component and a chromium group element component form a solid solution.

The present invention relates to a hydrocarbon adsorbent with metal-impregnated zeolite particles having regular mesopores and a manufacturing method therefor. The hydrocarbon adsorbent includes a metal cation and a metal oxide that are impregnated in zeolite particles, in particular, the zeolite particles include regularly formed mesopores having a size of 2 to 10. By adjusting a Si/Al ratio and mesoporosity of the mesopores, a hydrocarbon adsorbent may have increased adsorption capacity for hydrocarbons in a cold-start section and can rapidly oxidize the hydrocarbon upon desorption thereof, thereby reducing the discharge of exhaust gas produced in automobiles and industries.