Method for the catalytic oxidation of volatile organic compounds

A method for preparing a catalyst comprising a nonstoichiometric crystalline compound conventionally designated by a formula which corresponds to Sr14Cu24O41 comprising the steps of:

• a) immersing a pre-dried granular porous substrate material in an aqueous solution with a molar concentration of Sr(NO3)2 from 0.23 M to 0.93 M and a molar concentration of Cu(NO3)2 from 0.39 M to 1.59 M;
• b) drying the product of step a) at a temperature from 80° C. to 120° C.;
• and
• c) holding the product of step b) at a temperature from 650° C. to 750° C. in a gas stream which contains oxygen until complete decomposition of the nitrates occurs.

A method for preparing a catalyst comprising a nonstoichiometric crystalline compound conventionally designated by a formula which corresponds to Ca4Cu5O10 comprising the steps of:

• a) immersing a pre-dried granular porous substrate material in an aqueous solution of Ca(NO3)2 and Cu(NO3)2 in an equimolar ratio and at a molar concentration from 0.39 M to 1.39 M;
• drying the product of step a) at a temperature from 80° C. to 120° C.;
• and
• b) holding the product of step b) at a temperature from 650° C. to 750° C. in a gas stream which contains oxygen until complete decomposition of the nitrates occurs.

A method for preparing a catalyst comprising a non-stoichiometric crystalline compound conventionally designated by a formula which corresponds to Ca4Cu5O10, comprising the steps of:

• a) immersing a pre-dried granular porous substrate material in an aqueous solution obtained by dissolving, with the application of heat, CuO and CaCO3 in nitric acid, so that the molar ratio between the components of the solution is CuO:CaCO3:HNO3=1:0.83:3.2;
• water and citric acid being added thereto so that the citric acid:
• Cu molar ratio is from 3.5:1 to 4.0:1;
• b) heating the product of step a) in air until combustion of the organic fraction of the absorbed material is achieved;
• and
• c) thermal treating the product of step b) for 4 to 24 hours at a temperature from 650 to 750° C. in a stream of gas containing oxygen.