This review is a compendium of major research in the area of photocatalytic deNOx technologies. Largely, the research can be divided into two major heads: photocatalytic oxidation (PCO) and photocatalytic reduction (PCR) though photocatalytic decomposition is also a viable technology. In this article, major emphasis has been given to the materials and mechanisms developed for the various reactions. Many further studies are needed on the technologies of photocatalytic NOx abatement in terms of research work followed by commercialization. After discussing many studies, an overall conclusion is drawn with the potential future research direction in photocatalytic de-NOx investigation. © 2015 Bentham Science Publishers.