Enzyme catalyzed preparation of hollow alumina precursor using emulsion template

Hollow alumina precursor was prepared by the enzyme-inspired precipitation onto o/w emulsion using urease. Decomposition of urea by urease increased t he pH of the solution to hydrolyze aluminum sulfate. The advantages of the enzymatic reaction are that the apparent precipitation rate could be contro lled by the enzyme concentration of urease, and that the precipitation coul d take place without the destruction of emulsion. Hollow particles were obt ained at enzyme concentrations ranging between 10 and 50 mg/l. The destruct ion of the emulsion occurred at enzyme concentrations < 10 mg/l while nucle ation took place spontaneously in the solution at enzyme concentrations > 5 0 mg/l. Hollow powders with the phase of pseudo-boehmite, maintained their apparent shape after transformation into or-alumina at 1300 degreesC.