Characterization of wet processed (Ni, Zn)-ferrites for CO2 decomposition

Ultrafine (Ni, Zn)-ferrites were prepared by two different methods of coprecipitation and hydrothermal synthesis, and their oxygen-deficient ferrites (ODF) produced by hydrogen reduction were investigated on the efficiency of CO2 decomposition. The crystalline sizes of (Ni, Zn)-ferrites were less than 30 nm with high Brunauer-Emmett-Teller (BET) surface areas, ranging from 77 to 172 m(2) g(-1). The (Ni, Zn)-ferrites by hydrothermal synthesis resulted in smaller crystalline sizes, higher BET surface areas and better efficiencies of CO2 decomposition than by coprecipitation. Compared with the binary NiFe2O4-delta ferrite, the ternary (Ni-x, Zn-1-x) Fe2O4-(delta) ferrites showed higher efficiency for CO2 decomposition, indicating a potential catalyst for the reduction of CO2 emission in the environmental atmosphere. (C) 2001 Kluwer Academic Publishers.