Preparation and characterisation of high surface area semiconducting oxides

The conventional method of preparing doped semiconducting oxides involves solid state sintering at elevated temperatures and the resultant products have a very low surface area (< 1 m² g^–1). This severely limits the activity of semiconducting oxide catalysts, such as lithiated NiO. A cryochemical method based on the freeze drying of mixed salt solutions, followed by low temperature calcining has yielded lithiated NiO of over 60 m² g^–1. DTA, conductivity measurements and chemical analyses confirmed that under these conditions, very uniform mixing between Li₂O and NiO is achieved and that Li₂O can diffuse into the NiO lattice at about 400° C, as compared to 950 to 1000° C for products prepared by conventional means.