Influences of preparation parameters on the structural and catalytic performance of zirconia in isosynthesis

The influences of precipitation pH, zirconium salt precursors and the calci nation temperatures on the crystal structure and catalytic performance of z irconia in isosynthesis have been studied. The results indicated that the c atalytic performance of zirconia in isosynthesis was strongly influenced by the pH of precipitating solution, zirconium salt precursors and the calcin ation temperatures, However, the crystal phase of zirconia was not so sensi tively dependent on the pH. Monoclinic was always the main crystal phase wh en the value of pH was changed in the range of 6-14. Zirconia prepared from Zr(NO3)(4), ZrCl4, ZrOCl2 were monoclinic/tetragonal, but monoclinic was t he dominant phase. Zirconia prepared from Zr(SO4)(2) was a mixture of tetra gonal/amorphous. Even trace of SO42- involved in the gel, the crystallizati on of zirconia was delayed, the phase transformation from tetragonal to mon oclinic being inhibited, (C) 2000 Elsevier Science B.V. All rights reserved .