A new method for catalyst preparation is described, in which a precipitated catalyst is formed at the interface of fine bubbles and a liquid. This method was used to prepare Cu-ZnO-Al2O3 catalyst by introducing fine bubbles of ammonia into a mixed aqueous solution of metal nitrates under carbon dioxide flow and its activity was tested for the methanol decomposition reaction. Specific surface area of the newly developed fine bubble catalyst (FBC) was 94 sq m/g and 1.5 times larger than that of conventional catalyst (CVC) prepared by co-precipitation of mixed metallic aqueous solution and sodium carbonate. SEM demonstrated that the FBC particles were spherical of around 3 μm diameter and homogeneous. CVC particles were irregular in size and shape. SEM-EDX showed aggregation of copper in the CVC but good dispersion of all elements in the FBC. FBC had higher activity and less deactivation in the methanol decomposition reaction compared with CVC even at 623-673 K although the reaction time was only 10 hr.
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