The United States of America As Represented by the Administrator of the

Irvin M Miller

Billy T Upchurch

Kenneth G Brown

David R Schryer

George M Wood

Patricia P Davis

Barry D Sidney

Robert V Hess

David R Brown

John D Van Norman

Patricia A Davis

Ronald F Hoyt

Patricia A Paulin

A catalyst for the combination of CO and O.sub.2 to form CO.sub.2 which includes a platinum group metal--e.g., platinum; a reducible metal oxide having multiple valence states--e.g., SnO.sub.2 ; and a compound which can bind water to its structure--e.g., silica gel. This catalyst is ideally suited for application to high-powered, pulsed, CO.sub.2 lasers operating in a sealed or closed-cycle condition.

Catalyst for carbon monoxide oxidation

A quantity of reagent grade tin metal or compound, chloride-free, and high-surface-area silica spheres are placed in deionized water, followed by deaerating the mixture by boiling and adding an oxidizing agent, such as nitric acid. The nitric acid oxidizes the tin to metastannic acid which coats the spheres because the acid is adsorbed on the substrate. The metastannic acid becomes tin-oxide upon drying and calcining. The tin-oxide coated silica spheres are then placed in water and boiled. A chloride-free precious metal compound in aqueous solution is than added to the mixture containing the spheres, and the precious metal compound is reduced to a precious metal by use of a suitable reducing agent such as formic acid. Very beneficial results have been obtained using the precious metal compound tetraammine platinum(II) hydroxide.

Process for making a noble metal on tin oxide catalyst

A method of exchanging rare-isotope oxygen for common-isotope oxygen in the top several layers of an oxide-containing catalyst is disclosed. A sample of an oxide-containing catalyst is exposed to a flowing stream of reducing gas in an inert carrier gas at a temperature suitable for the removal of the reactive common-isotope oxygen atoms from the surface layer or layers of the catalyst without damaging the catalyst structure. The reduction temperature must be higher than any at which the catalyst will subsequently operate. Sufficient reducing gas is used to allow removal of all of the reactive common-isotope oxygen atoms in the top several layers of the catalyst. The catalyst is then reoxidized with the desired rare-isotope oxygen in sufficient quantity to replace all of the common-isotope oxygen that was removed.

Isotope exchange in oxide-containing catalyst

A method for the reactivation of a tin oxide-containing catalyst of a CO.sub.2 laser is provided. First, the catalyst is pretreated by a standard procedure. When the catalyst experiences diminished activity during usage, the heated zone surrounding the catalyst is raised to a temperature which is the operating temperature of the laser and 400.degree. C. for approximately one hour. The catalyst is exposed to the same laser gas mixture during this period. The temperature of the heated zone is then lowered to the operating temperature of the CO.sub.2 laser.

Reactivation of a tin oxide-containing catalyst

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Newport News, VA, United States of America

Irvin M Miller