Photocatalytic studies of antimonate compounds prepared by a self-combustion route

Antimonates compounds with 1Ca:1Sb and 2Ca:1Sb:1Al compositions were synthesized by a self-combustion method. For the 1Ca:1Sb composition, a calcination at 1573 K led to a pure Ca2Sb2O7 weberite phase, whose structure was determined using the Rietveld method. In the case of the 2Ca:1Sb:1Al composition, a pure phase was achieved at 1073 K, and the use of higher calcination temperatures led to a mixture of phases. Some of the products (1Ca:1Sb (873 K), 2Ca:1Sb:1Al (1073 K) and Ca2Sb2O7 (1573 K)) were tested as photocatalysts for the methyl orange degradation. The results clearly demonstrated that Ca2Sb2O7 is the catalyst exhibiting the best results for the MO photocatalytic degradation. This fact was interpreted as due to a predominant role of structural features on the photocatalytic activity of the prepared compounds.