A process for preparing aldehydes by a homogeneously catalysed hydroformylation of C.sub.4 to C.sub.20 olefins involves withdrawing a biphasic stream (liquid/gaseous) and expanding in two stages. Before, between, or after the two stages, the liquid phase is cooled. Only after expansion and cooling is the homogeneously dissolved rhodium catalyst system separated from the residual stream.

Provided is an exhaust gas purification device that ensures an improved purification performance and a suppressed pressure loss. An exhaust gas purification device of the present disclosure includes a honeycomb substrate and an inflow cell side catalyst layer. disposed on a surface on the inflow cell side in an inflow side region of the partition wall. When a gas permeability coefficient of an inflow side partition wall portion including the inflow side region of the partition wall and the inflow cell side catalyst layer is Ka and a gas permeability coefficient of an outflow side partition wall portion including an outflow side region at least from the predetermined position to an outflow side end of the partition wall is Kb, a ratio Ka/Kb of the gas permeability coefficients is within a range of 0.4 or more and 0.8 or less.

A particulate filter disclosed herein includes a wall-flow structure substrate 10 and a wash coat layer 20 held inside a partition 16 of the substrate 10. The wash coat layer 20 includes an inlet layer 22 formed to have predetermined length L.sub.A and thickness T.sub.A from near an end thereof on an exhaust gas inflow side X1, and an outlet layer 24 formed to have predetermined length L.sub.B and thickness T.sub.B from near an end thereof on an exhaust gas outflow side X2. The inlet layer 22 and the outlet layer 24 partially overlap each other. In the particulate filter disclosed herein, the inlet layer 22 contains a precious metal catalyst, while the outlet layer 24 contains substantially no precious metal catalyst. The length L.sub.A of the inlet layer is 50% or more and 75% or less of a total length L of the partition 16. Thus, the particulate filter is capable of achieving both PM collection performance and pressure-drop reduction performance at high levels.

An exhaust gas purification system for a gasoline engine is described the system comprising in consecutive order the following devices: •a first three-way-catalyst (TWC1), a gasoline particulate filter (GPF) and a second three-way-catalyst (TWC2), •wherein the oxygen storage capacity (OSC) of the GPF is greater than the OSC of the TWC1, wherein the OSC is determined in mg/l of the volume of the device.

The present invention relates to a catalyst for the oxidation of NO, for the oxidation of ammonia and for the selective catalytic reduction of NOx, comprising a substrate, a first coating comprising one or more of a vanadium oxide and a zeolitic material comprising one or more of copper and iron; and a second coating comprising a platinum group metal component supported on a non-zeolitic oxidic material, wherein the second coating further comprises a zeolitic material comprising one or more of copper and iron.

The presently invention provides an emission control catalyst article comprising a substrate, a bottom washcoat layer comprising a platinum group metal coated on the 60 to 100% length of the substrate, and a top washcoat layer comprising a platinum group metal coated on the 60 to 100% length of the substrate such that the top coat covers at least 60% of the length of the bottom washcoat layer, wherein at least a portion of the top washcoat layer, the bottom washcoat layer or both washcoat layers comprises a platinum group metal deposited within the said washcoat layer(s) with a platinum group metal gradient such that the PGM concentration in a top-most portion of the said washcoat layer is at least two time higher compared to the PGM concentration in a bottom-most portion of the said washcoat layer.

The present invention relates to silver nanoclusters doped with rhodium hydride, a method of producing the same, and an electrochemical catalyst for hydrogen gas generation. The silver nanoclusters doped with rhodium hydride of the present invention have utility as an electrochemical catalyst, have a significantly low production cost compared to a platinum (Pt) catalyst according to the related art, and exhibit an effect of generating hydrogen gas equal to or greater than that of the Pt catalyst.

A three-way catalyst article with improved ammonia emission control, and its use in an exhaust system for gasoline engines, is disclosed. The catalyst article for treating exhaust gas from a gasoline engine comprising: a substrate comprising an inlet end, an outlet end with an axial length L; a first catalytic region beginning at the inlet end, wherein the first catalytic region comprises a first zeolite; and a second catalytic region beginning at the outlet end, wherein the second catalytic region comprises a second platinum group metal (PGM) component, a second oxygen storage capacity (OSC) material, and a second inorganic oxide; wherein the second PGM component is selected from the group consisting of palladium, platinum, rhodium and a combination thereof.

The present disclosure relates to a multi-sandwich composite catalyst and a preparation method and application thereof. The present disclosure provides a preparation method of a multi-sandwich composite catalyst, comprises the following steps: sequentially depositing a first layer oxide, a first active metal, an oxide interlayer, a second active metal and a surface oxide on a template, and sequentially performing calcination and reduction, thereby obtaining a multi-sandwich composite catalyst; wherein the first active metal and the second active metal are different kinds of active metals. In the present disclosure, a multi-sandwich structure is formed by depositing the oxides and active metals alternately, so that the position and spacing distance of the active centers can be precisely controlled. The multi-sandwich composite catalyst prepared by the method provided described herein has a higher conversion than that of a catalyst without an interlayer when used for the catalytic reaction.

The present invention relates to a three-way catalyst (TWC) for treatment of exhaust gases from internal combustion engines operated with a predominantly stoichiometric air/fuel ratio, so called spark ignited engines.