TWC ACTIVITY USING RHODIUM/PLATINUM AND GALLIC ACID AS A COMPLEXING AND REDUCING AGENT

1 . A method of manufacturing a catalyst article, the method comprising:

providing a complex of a compound of formula (I):

and a PGM, R1 is H or C 1 -C 6 alkyl, R2 is H, OH, or O—C 1 -C 4 alkyl, the PGM comprising rhodium and/or platinum;

providing a support material;

applying the complex to the support material to form a loaded support material;

disposing the loaded support material on a substrate; and

heating the loaded support material to form nanoparticles of the PGM on the support material.

2 . The method of claim 1 , wherein R2 is OH.

3 . The method of claim 1 , wherein R1 is H.

4 . The method of claim 1 , wherein the support material comprises an oxide, preferably one of more of Al 2 O 3 , SiO 2 , TiO 2 , Ce 2 O 2 , ZrO 2 , Ce 2 O 2 —ZrO 2 , V 2 O 5 , La 2 O 3 and zeolites.

5 . The method of claim 4 , wherein the support material comprises alumina and/or ceria-zirconia.

6 . The method of claim 5 , wherein the alumina and/or ceria-zirconia is doped.

7 . The method of claim 6 , wherein the alumina and/or ceria-zirconia is doped with an oxide of one or more of lanthanum, neodymium, yttrium, niobium, praseodymium, hafnium, molybdenum, titanium, vanadium, zinc, cadmium, manganese, iron, copper, calcium, barium, strontium, caesium, magnesium, potassium and sodium, preferably one or more of lanthanum, neodymium and yttrium.

8 . The method of claim 1 , wherein the loaded support material is disposed on the substrate in the form of a slurry.

9 . The method of claim 8 , wherein the slurry is prepared by a method comprising:

contacting a PGM salt and a compound of formula (I) in water to form the complex of a compound of formula (I) and a PGM in an aqueous solution, the PGM salt comprising rhodium and/or platinum;

applying the complex to the support material to form a loaded support material by contacting the support material with the aqueous solution;

optionally adding one or more of an oxygen storage material, preferably ceria-zirconia;

a promoter salt; a binder; an acid or a base; a thickening agent; and a reducing agent to the aqueous solution.

10 . The method of claim 8 , further comprising disposing a further slurry on the substrate, the further slurry comprising one or more of a further support material; an oxygen storage material; a promoter salt; a binder; an acid or a base; a thickening agent; and a reducing agent, wherein disposing the further slurry on the substrate takes place before disposing the support material on the substrate and/or after heating the loaded support material to form nanoparticles of the PGM on the support material.

11 . The method of claim 1 , wherein the substrate is in the form of a honeycomb monolith, a wall flow filter or a flow through filter.

12 . A catalyst article obtainable by the method of claim 1 , the catalyst article for use in an emission treatment system.

13 . The catalyst article of claim 12 for three-way catalysis.

14 . The catalyst article of claim 12 comprises a bottom layer of support material having rhodium thereon and a top layer of support material having palladium thereon.

15 . The catalyst article of claim 12 comprising a bottom layer of support material having palladium thereon and a top layer of support material having rhodium thereon.

16 . An emission treatment system comprising the catalyst article of claim 12 .

17 . The emission treatment system of claim 16 for a gasoline engine.

18 . The emission treatment system of claim 17 , wherein the gasoline engine operates under stoichiometric conditions.

19 . A method of treating an exhaust gas, the method comprising:

providing the catalyst article of claim 12 ; and

contacting the catalyst article with an exhaust gas.

20 . The method of claim 19 , wherein the exhaust gas is from a gasoline engine.