An exhaust-gas purification system of an internal combustion engine includes an electrically heated catalytic device and a three-way catalytic device. The electrically heated catalytic device includes a first honeycomb base having a large number of honeycomb passages and a first catalyst component that is supported on, by a predetermined thin-film treatment, surfaces that define the honeycomb passages and that contains one or more types of noble metals. The three-way catalytic device includes a second honeycomb base having a large number of honeycomb passages and a second catalyst component that is supported on surfaces defining the honeycomb passages and that contains one or more types of noble metals. The total noble metal content per unit volume of the second honeycomb base is higher than the total noble metal content per unit volume of the first honeycomb base.

A metal honeycomb substrate includes a tubular body, a flat plate, and a wavy plate. The tubular body has a receiving portion. The wavy plate is stacked with the flat plate to form a spiral structure received in the receiving portion. The wavy plate has a wavy-shaped cross section and includes a second region and a continuous region connected to the second region. The wavy-shaped cross section includes peak portions and valley portions. The wavy plate has a solder region overlapping at least one portion of at least one of the second region and the continuous region. Solders are on outer sides of the peak portions and outer sides of the valley portions which are in the solder region. A ratio of an area of the solder region to an area of the wavy plate is in a range between substantially 20% and substantially 66%.

An exhaust aftertreatment system includes a cross-flow selective catalytic reduction catalyst. The cross-flow selective catalytic reduction catalyst includes a housing and a substrate assembly. The substrate assembly includes a plurality of first substrate layers defining a plurality of first flow channels and a plurality of second substrate layers defining a plurality of second flow channels. The exhaust aftertreatment system includes a passive NO.sub.x adsorber. The passive NO.sub.x adsorber includes a housing. The housing includes an inlet in exhaust gas receiving communication with the plurality of first flow channels of the cross-flow selective catalytic reduction catalyst. The housing includes an outlet in exhaust gas providing communication with the plurality of second flow channels of the cross-flow selective catalytic reduction catalyst. The passive NO.sub.x adsorber includes a substrate positioned in the housing. The substrate includes a passive NO.sub.x adsorber washcoat.

An exhaust device discharging exhaust gas from an engine of a ship propulsion machine includes an exhaust passage through which the exhaust gas flows and a catalyst device purifying the exhaust gas. The exhaust passage includes a first exhaust pipe and a second exhaust pipe connected to an outflow side of the first exhaust pipe. The catalyst device includes a metal catalyst including a metal catalyst carrier, an outer shell portion having a tubular shape and accommodating the metal catalyst, and a holding portion provided in the outer shell portion, having a brim shape protruding radially outward beyond an outer circumferential surface of the outer shell portion, and holding the catalyst device. The catalyst device is held in the exhaust passage by the holding portion being sandwiched between an outflow-side end portion of the first exhaust pipe and an inflow-side end portion of the second exhaust pipe.

An exhaust gas purification device that allows suppressing an increase in pressure loss is provided. The exhaust gas purification device of the present disclosure includes a honeycomb substrate and an inflow cell side catalyst layer. The substrate includes a porous partition wall which defines inflow cells and outflow cells extending from an inflow side end to an outflow side end. The inflow cell side catalyst layer is disposed on a surface on the inflow cell side in an inflow cell side catalyst region from an inflow side end to a position close to an outflow side end of the partition wall. The permeability of a portion including an outflow side region from the position to the outflow side end of the partition wall is higher than a gas permeability of a portion including the inflow cell side catalyst region of the partition wall and the inflow cell side catalyst layer.

A method of making a titanium dioxide nanowire array includes contacting a substrate with a solvent comprising a titanium (III) precursor, an acid, and an oxidant while microwave heating the solvent, thereby forming a hydrogen titanate H2Ti2O5.H2O nanowire array. The hydrogen titanate nanowire array is annealed to form a titanium dioxide nanowire array. The substrate is seeded with titanium dioxide before starting the hydrothermal synthesis of the hydrogen titanate nanowire array. The titanium dioxide nanowire array is loaded with a platinum group metal to form an exhaust gas catalyst. The titanium dioxide nanowire array can be used to catalyze oxidation of combustion exhaust.

The present invention relates to a compressed natural gas combustion and exhaust system comprising: (i) a natural gas combustion engine; and (ii) an exhaust treatment system, the exhaust treatment system comprising a intake for receiving an exhaust gas from the combustion engine and a catalyst article arranged to receive and treat the exhaust gas, wherein the catalyst article comprises: a substrate having at least first and second coatings, the first coating being free from platinum-group-metals and comprising a copper-containing zeolite having the CHA framework-type and the second coating comprising a palladium-containing zeolite, wherein the first coating is arranged to contact the exhaust gas before the second coating. The present invention further relates to a method and a use.

An exhaust gas purification device includes a substrate including an upstream end and a downstream end and having a length Ls; a first containing Pd particles, extending between the upstream end and a first position, and being in contact with the substrate; a second containing Rh particles, extending between the downstream end and a second position, and being in contact with the substrate; and a third catalyst layer containing Rh particles, extending between the upstream end and a third position, and being in contact with at least the first catalyst layer, wherein an average of a Rh particle size distribution is from 1.0 to 2.0 nm, and a standard deviation of the Rh particle size distribution is 0.8 nm or less in each of the second catalyst layer and the third catalyst layer.

The present invention relates to a methane combustion catalyst including platinum and iridium supported on a tin oxide carrier for combusting methane in a combustion exhaust gas containing sulfur oxide. In the methane combustion catalyst, a ratio R.sub.TO of platinum oxides to metal platinum is 8.00 or more, wherein the ratio R.sub.TO is based on existence percentages of the metal platinum (Pt) and the platinum oxides (PtO and PtO.sub.2) obtained from a platinum 4f spectrum analyzed and measured by X-ray photoelectron spectroscopy (XPS) and calculated in accordance with the following expression. In the following expression, R.sub.Pt is an existence percentage of the metal platinum (Pt), R.sub.Pto is an existence percentage of PtO, and R.sub.Pto2 is an existence percentage of PtO.sub.2.

R.sub.TO=(R.sub.PtO+R.sub.PtO2)/R.sub.Pt  [Expression 1]

A honeycomb body includes at least a housing and a honeycomb structure having a plurality of channels. The honeycomb structure is formed of at least one at least partially structured metallic layer that forms connecting points fixing the honeycomb structure. At most 20% of inner contact points in a cross section of the honeycomb structure form a connection point, and the connection points are disposed at a distance from each other in such a way that respective connection-free regions of the same size surround each of the connection points. An exhaust-gas purification unit and a motor vehicle are also provided.