Water gas shift process

In a process for the preparation of hydrogen which comprises contacting a gas mixture comprising carbon monoxide and steam and less than about 200 vppm of a sulfur material in a reaction zone at a temperature varying from about 200.degree. F. to 925.degree. F. and at an elevated pressure with a catalyst to form a reaction mixture, the temperature within said reaction zone being maintained above the dew point temperature of the reaction mixture and the pressure within said reaction zone being maintained below the dew point pressure of the reaction mixture, said catalyst comprising (i) an alkali metal compound derived from an acid having an ionization constant less than about 1 .times. 10.sup.-3, (ii) a hydrogenation-dehydrogenation component comprising (a) the oxides or sulfides of vanadium, molybdenum, tungsten, or cobalt or mixtures thereof, and (b) mixtures of the oxides or sulfides of vanadium, molybdenum, tungsten, or cobalt or mixtures thereof with the oxides or sulfides of nickel, iron or chromium or mixtures thereof, said catalyst being contained on a support with at least a portion of said alkali metal compound or hydrogenation-dehydrogenation component being in a sulfide form, the weight ratio of said hydrogenation-dehydrogenation component to said alkali metal compound, each calculated on the basis of the oxide thereof, being in the range of about 0.001:1 to about 5:1, the oxides or sulfides of nickel, iron or chromium making up less than about 80 mole % of the total hydrogenation-dehydrogenation component, the improvement which comprises incorporating at least 0.01 weight % of a chlorine component into said catalyst, thereby improving the activity maintenance characteristics of said catalyst.