Abstract: Provided are a hydrocarbon adsorbent, an exhaust gas purifying catalyst, and an exhaust gas purifying system, which are capable of adsorbing hydrocarbons, storing the adsorbed hydrocarbons up to a relatively high temperature, and desorbing the adsorbed and stored hydrocarbons at a relatively high temperature. The hydrocarbon adsorbent contains a multipore zeolite containing, outside the zeolite framework, at least one metal selected from the group consisting of transition metals belonging to Groups 3 to 12 in the periodic table, amphoteric metals belonging to Groups 13 and 14 in the periodic table, alkali metals, and alkaline earth metals; and has a content ratio of the metal of 9% by mass or less relative to the multipore zeolite containing the metal.

Abstract: Provided are: a hydrocarbon adsorbent capable of adsorbing hydrocarbons, storing the adsorbed hydrocarbons up to a relatively high temperature, and desorbing the adsorbed and stored hydrocarbons at a relatively high temperature; an exhaust gas purifying catalyst composition using the same; an exhaust gas purifying catalyst; and a method for treating an exhaust gas. The hydrocarbon adsorbent comprises a zeolite having an MRT-type framework structure. The hydrocarbon adsorbent comprises a small-pore zeolite having a total desorption amount ZD1 of propylene desorbed at 50° C. or higher and lower than 300° C. being 3.5 mmol/g or less and a total desorption amount ZD2 of propylene desorbed at 300° C. or higher and 500° C. or lower being 0.5 mmol/g or more, per 1 g by mass of the small-pore zeolite, when adsorbing propylene at 50° C. and then heating from 50° C. to 500° C. under the condition of 10° C./min by a temperature-programmed desorption method.

Abstract: Provided are: an exhaust gas purifying composition that contains a phosphorus-containing BEA-type zeolite and has further improved heat resistance; and a production method therefor. The exhaust gas purifying composition contains a phosphorus-containing BEA-type zeolite, wherein the phosphorus-containing BEA-type zeolite has a pore volume ratio (V2/V1) of a micropore volume V2 having a pore diameter in a range of 2 nm or less, as measured by a SF method, to a mesopore volume V1 having a pore diameter in a range of 2 nm or more and 100 nm or less, as measured by a BJH method, of 2.0 or more.

Abstract: An exhaust gas purification device for an internal combustion engine is provided in an exhaust passage of the internal combustion engine. The exhaust gas purification device includes an HC trapping converter comprising a carrier; an HC adsorbing layer, supported on the carrier and adapted to adsorb unburned fuel; and a ternary catalyst layer, supported on a surface of the HC adsorbing layer and adapted to oxidize and remove the unburned fuel. The HC adsorbing layer includes particulate HC adsorbents each of which has a follow space and which are stacked. The ternary catalyst layer covers the HC absorbing layer such that a thickness of the ternary catalyst layer increases from an upstream side to a downstream side of the converter in the direction of exhaust gas flow.

Abstract: An exhaust gas purification device for an internal combustion engine is provided in an exhaust passage of the internal combustion engine. The exhaust gas purification device includes: a carrier; an HC adsorbing layer, supported on the carrier and adapted to adsorb unburned fuel; and a ternary catalyst layer, supported on a surface of the HC adsorbing layer and adapted to oxidize and remove the unburned fuel. The HC adsorbing layer includes particulate HC adsorbents each of which has a follow space and which are stacked.

Abstract: The invention relates to an HC trap catalyst and a preparation method for the HC trap catalyst. The HC trap catalyst includes an HC adsorbent for adsorbing HC in exhaust gas exhausted from an internal combustion engine, and an oxidation accelerating element contained in the HC adsorbent for accelerating partial oxidation of the HC adsorbed by the HC adsorbent. With the above configuration, HC in exhaust gas can be partially oxidized. As a result, the oxidation reactivity of HC can be improved remarkably. Further, since the oxidation accelerating element is contained in the HC adsorbent, the HC adsorbed in the HC adsorbent can be partially oxidized directly. As a result, the partial oxidation can be promoted efficiently.