Review of SO 2− 4 /M x O y solid superacid catalysts

Some metal oxides modified with sulfate ions form highly acidic or superacidic catalysts. SO 2− 4 /M x O y solid superacid catalysts, play a vital role in more and more fields such as organic synthesis, fine chemicals, pharmaceuticals, and means for strengthening environmental safeguards. This review highlights the recent development of solid superacid catalysts based on SO 2− 4 /M x O y , including synthesis method, characterization of acid sites and acid strength, and applications.