A new technique for preparing ceramics for catalyst support exhibiting high porosity and high heat resistance

A new technique for preparing magnesia ceramics of high porosity and high t emperature resistance has been developed. Spray freeze drying of magnesium sulfate aqueous solution produced fine salt particles having open pores due to sublimation of ice crystals. The particles were calcined to porous magn esium oxide and formed a green body. Highly porous magnesia was produced by firing the green body. The porous magnesia exhibited a bimodal pore size d istribution of macro-pores of micron order and meso-pores smaller than 100 nm. Porosity was 87-90%. After addition of an aluminum additive with an amo unt 3-5 mol%, the magnesia exhibited high heat resistance; surface area was greater than 20 m(2) g(-1) after 20 h exposure in a 1573 K oven. Thus, the porous magnesia is expected to be very suitable for combustion catalyst su pport used in a high temperature environment. (C) 2001 Elsevier Science B.V . All rights reserved.