The aim of this work is to point out a number of controversies in the results of research on catalytic ozonation, discuss them and indicate their possible reasons. The existing literature has provided many quite well documented proposals of possible mechanisms of catalytic ozonation. However, a closer analysis of all these proposals reveals that many of them are simply contradictory. The number of controversies in the field of catalytic ozonation may indicate our poor understanding of the mechanisms of the process. It is also possible that the reasons for the controversies lie in some basic experimental errors. (c) 2013 Elsevier B.V. All rights reserved.