The present application relates to a multifunctional filter medium and a method of manufacturing the same. The multifunctional filter medium of the present application is capable of significantly reducing fine dust, harmful microorganisms, and toxic gases and reducing a pressure decrease during filtration due to exclusion of high-density nanofiber, thereby minimizing energy required for filtration and exhibiting sufficient filtration performance as a single filter medium.

The present invention relates to a mixed oxide of aluminium, of zirconium, of cerium, of lanthanum and optionally of at least one rare-earth metal other than cerium and lanthanum that makes it possible to prepare a catalyst that retains, after severe ageing, a good thermal stability and a good catalytic activity. The invention also relates to the process for preparing this mixed oxide and also to a process for treating exhaust gases from internal combustion engines using a catalyst prepared from this mixed oxide.

Provided is a GPF capable of exhibiting better than conventional three-way purification function. A gasoline particulate filter (GPF) that is provided in an exhaust pipe of an engine and that performs purification by capturing particulate matter (PM) in exhaust gas is provided with a filter substrate in which a plurality of cells extending from an exhaust gas inflow-side end face to an outflow-side end face are defined by porous partition walls and in which openings at the inflow-side end face and openings at the outflow-side end face of the cells are alternately sealed; and a three-way catalyst (TWC) supported by the partition wall. The three-way catalyst is the GPF comprising a catalytic metal containing at least Rh, and a composite oxide having an oxygen storage capacity and containing Nd and Pr in a crystal structure.

The present disclosure describes hybrid binary catalysts (HBCs) that can be used as engine aftertreatment catalyst compositions. The HBCs provide solutions to the challenges facing emissions control. In general, the HBCs include a porous primary catalyst and a secondary catalyst. The secondary catalyst partial coats the surfaces (e.g., the internal porous surface and/or the external surface) of the primary catalyst resulting in a hybridized composition. The synthesis of the HBCs can provide a primary catalyst whose entire surface, or portions thereof, can be coated with the secondary catalyst.

Disclosed herein are a catalyst composition, catalyst devices, and methods for removing formaldehyde, volatile organic compounds, and other pollutants from an air flow stream. The catalyst composition including manganese oxide, optionally one or more of alkali metals, alkaline earth metals, zinc, iron, binder, an inorganic oxide, or carbon.

Systems are provided for a diesel oxidation catalyst. In one example, the diesel oxidation catalyst comprises a washcoat with different catalytically active portions for reacting with one or more of carbon containing compounds and NO.sub.x. The diesel oxidation catalyst is located upstream of a particulate filter in an exhaust passage.

An oxygen storage material comprises a CeZr-Ln-Ti-based composite oxide containing cerium (Ce), zirconium (Zr), a rear-earth element (Ln: excluding cerium), and titanium (Ti), wherein at least part of the rear-earth element and at least part of the titanium are solid-dissolved in a composite oxide of the cerium and the zirconium, and the CeZr-Ln-Ti-based composite oxide has a composition expressed by the following chemical formula (1):
Ce.sub.a-xLn.sub.xZr.sub.b-yTi.sub.yO.sub.(1),
where a, b, x, and y are numbers satisfying conditions of a=0.4 to 0.6, b=0.4 to 0.6, x=0 to a (exclusive of x=0 and x=a), y=0 to 0.3 (exclusive of y=0), and a+b=1, and is a number of 1.7 to 2.2.

Zeolite catalysts and systems and methods for preparing and using zeolite catalysts having the CHA crystal structure are disclosed. The catalysts can be used to remove nitrogen oxides from a gaseous medium across a broad temperature range and exhibit hydrothermal stable at high reaction temperatures. The zeolite catalysts include a zeolite carrier having a silica to alumina ratio from about 15:1 to about 256:1 and a copper to alumina ratio from about 0.25:1 to about 1:1.

A method for treating the waste stream from a purified terephthalic acid (PTA) process is provided. The method comprises contacting a waste stream containing carbon monoxide (CO), volatile organic compounds (VOCs), and methyl bromide with a catalyst comprising a first base metal catalyst supported on an oxygen donating support that is substantially free of alumina, and at least one second base metal catalyst.

An apparatus for purifying exhaust gas includes: an engine; an exhaust gas air-fuel ratio adjustor for adjusting an air-fuel ratio of the exhaust gas; a lean NO.sub.x trap (LNT) mounted on the exhaust pipe and generating ammonia or reducing nitrogen oxides or desorbed nitrogen oxides contained in the exhaust gas using a reducing agent including carbon monoxide, hydrocarbon, or hydrogen contained in the exhaust gas; a three way catalyst (TWC) mounted on the exhaust pipe at a rear end of the LNT, and converting noxious gas in the exhaust gas into harmless components through a redox reaction; and a controller controlling the air-fuel ratio of the exhaust gas to a stoichiometric air-fuel ratio when the nitrogen oxide storage or purification performance of the LNT is in the operating period of the engine less than a predetermined level.