Catalyst for water gas shift reaction at middle temperature, preparation method thereof, and hydrogen preparation method using same

A method of preparing hydrogen, comprising providing a catalyst for a water gas shift reaction, to perform a water gas shift reaction,

• wherein the catalyst for the water gas shift reaction comprises a catalytically active component containing 40 to 80 mol % of copper (Cu), 15 to 50 mol % of zinc (Zn), and 1 to 13 mol % of aluminum (Al), relative to all metals of the catalyst,
• wherein an aluminum-rich layer is present in a surface layer of a particle of the catalyst,
• wherein the catalyst is prepared by a catalyst preparation method comprising a copper-zinc coprecipitation operation of injecting a metal precursor solution containing a Cu precursor and a Zn precursor into a precipitant solution to coprecipitate copper and zinc, to produce a copper-zinc coprecipitate;
• an Al precipitation operation of injecting an Al precursor solution into a solution containing the copper-zinc coprecipitate to precipitate aluminum on a surface of the copper-zinc coprecipitate, to prepare a CuZnAl catalyst precursor material having an aluminum-rich layer on a surface;
• and
• a baking operation of baking the CuZnAl catalyst precursor material to prepare a CuZnAl catalyst,
• wherein the copper-zinc coprecipitation operation is performed by aging a mixture of the metal precursor solution containing the Cu precursor and the Zn precursor, and the precipitant solution within a temperature range of room temperature (20° C.) to 80° C. for 30 to 180 minutes,
• wherein the Al precursor solution is injected, after a phenomenon after which a pH is reduced to a range of 0.05 to 0.2 and is then returned during the aging.