Provided is a combustion system using a catalyst having better denitration efficiency at low temperatures, during a selective catalytic reduction reaction in which ammonia is used as a reducing agent.

This combustion system comprises: a combustion device that combusts fuel; an exhaust path through which flows exhaust gas generated from the combustion of fuel in the combustion device; a dust collection device that is arranged on the exhaust path and collects ash dust/dust in the exhaust gas; and a denitration device that is arranged on the exhaust path and removes nitrogen oxides from the exhaust gas by means of a denitration catalyst, wherein the denitration device is arranged downstream of the dust collection device on the exhaust path, and the denitration catalyst contains vanadium oxide including vanadium pentoxide and has a defect site in which an oxygen atom is deficient in a crystal structure of the vanadium pentoxide.

Provided is a combustion system using a catalyst having better denitration efficiency at low temperatures, during a selective catalytic reduction reaction in which ammonia is used as a reducing agent.

This combustion system comprises: a combustion device that combusts fuel; an exhaust path through which flows exhaust gas generated from the combustion of fuel in the combustion device; a dust collection device that is arranged on the exhaust path and collects ash dust/dust in the exhaust gas; and a denitration device that is arranged on the exhaust path and removes nitrogen oxides from the exhaust gas by means of a denitration catalyst, wherein the denitration device is arranged downstream of the dust collection device on the exhaust path, and the denitration catalyst contains vanadium oxide including vanadium pentoxide and has a defect site in which an oxygen atom is deficient in a crystal structure of the vanadium pentoxide.

It is an object to provide a regenerated denitration catalyst whose denitration performance is restored compared with a denitration catalyst before use, utilizing a spent denitration catalyst, and a method for manufacturing the same. In a regenerated denitration catalyst according to the present disclosure, a spent denitration catalyst including a first titanium oxide as a main component, and a second titanium oxide are mixed. The spent denitration catalyst is already used in a denitration reaction in which nitrogen oxides in a gas are decomposed into nitrogen and water using a reducing agent. The second titanium oxide has a larger specific surface area per unit weight than the first titanium oxide. A content of the second titanium oxide based on a total weight of the first titanium oxide and the second titanium oxide is preferably 10% by weight or more and 90% by weight or less.

It is an object to provide a regenerated denitration catalyst whose denitration performance is restored compared with a denitration catalyst before use, utilizing a spent denitration catalyst, and a method for manufacturing the same. In a regenerated denitration catalyst according to the present disclosure, a spent denitration catalyst including a first titanium oxide as a main component, and a second titanium oxide are mixed. The spent denitration catalyst is already used in a denitration reaction in which nitrogen oxides in a gas are decomposed into nitrogen and water using a reducing agent. The second titanium oxide has a larger specific surface area per unit weight than the first titanium oxide. A content of the second titanium oxide based on a total weight of the first titanium oxide and the second titanium oxide is preferably 10% by weight or more and 90% by weight or less.

A hybrid photoactive heterojunction including a copper vanadate, Cu.sub.2V.sub.2O.sub.7 (CVO) and a zinc vanadate, Zn.sub.2V.sub.2O.sub.6 (ZVO). Particles of the ZVO are dispersed in particles of the CVO to form the hybrid photoactive heterojunction. The hybrid photoactive heterojunction in the form of a photoactive film includes a substrate which is at least partially coated with the hybrid photoactive heterojunction. A method of photodegrading a dye includes contacting the photoactive film and the dye in a solution and exposing the solution to light. A method of photoelectrochemically oxidizing water includes contacting the photoactive film with water in a solution and exposing the solution to light.

A hybrid photoactive heterojunction including a copper vanadate, Cu.sub.2V.sub.2O.sub.7 (CVO) and a zinc vanadate, Zn.sub.2V.sub.2O.sub.6 (ZVO). Particles of the ZVO are dispersed in particles of the CVO to form the hybrid photoactive heterojunction. The hybrid photoactive heterojunction in the form of a photoactive film includes a substrate which is at least partially coated with the hybrid photoactive heterojunction. A method of photodegrading a dye includes contacting the photoactive film and the dye in a solution and exposing the solution to light. A method of photoelectrochemically oxidizing water includes contacting the photoactive film with water in a solution and exposing the solution to light.

The present invention relates to a selective catalytic reduction catalyst for the treatment of an exhaust gas of a diesel engine comprising (i) a flow-through substrate comprising an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end and a plurality of passages defined by internal walls of the flow-through substrate extending therethrough; (II) a coating disposed on the surface of the internal walls of the substrate, where-in the surface defines the interface between the passages and the internal walls, wherein the coating comprises a vanadium oxide supported on an oxidic material comprising titania, and further comprises a mixed oxide of vanadium and one or more of iron, erbium, bismuth, cerium, europium, gadolinium, holmium, lanthanum, lutetium, neodymium, praseodymium, promethium, samarium, scandium, terbium, thulium, ytterbium, yttrium, molybdenum, tungsten, manganese, cobalt, nickel, copper, aluminum and antimony.

The present invention relates to a selective catalytic reduction catalyst for the treatment of an exhaust gas of a diesel engine comprising (i) a flow-through substrate comprising an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end and a plurality of passages defined by internal walls of the flow-through substrate extending therethrough; (II) a coating disposed on the surface of the internal walls of the substrate, where-in the surface defines the interface between the passages and the internal walls, wherein the coating comprises a vanadium oxide supported on an oxidic material comprising titania, and further comprises a mixed oxide of vanadium and one or more of iron, erbium, bismuth, cerium, europium, gadolinium, holmium, lanthanum, lutetium, neodymium, praseodymium, promethium, samarium, scandium, terbium, thulium, ytterbium, yttrium, molybdenum, tungsten, manganese, cobalt, nickel, copper, aluminum and antimony.

The invention relates to a catalyst device for purifying exhaust gases containing nitrogen oxide by means of selective catalytic reduction (SCR), comprising at least two catalytic regions, the first region containing vanadium oxide and cerium oxide, and the second region containing a molecular sieve containing iron. The invention also relates to uses, the catalyst device and methods for purifying exhaust gases.

A catalyst composition comprising (a) carrier comprising (i) 5 to 95 wt % mordenite type zeolite having a mean crystallite length parallel to the direction of the 12-ring channels of 60 nm or less and a mesopore volume of at least 0.10 cc/gram, (ii) 5 to 95 wt % ZSM-5 type zeolite; and (iii) 10 to 60 wt % inorganic binder; and (b) 0.001 to 10 wt % of one or more catalytically active metals, wherein the inorganic binder comprises titania, its preparation and its use in alkylaromatic conversion.