Hybridization of metal oxides with nanocarbons has become a very fertile soil of research, given the synergy of the two phases that results in most cases in an improved photo-catalytic performance. Despite the mechanism is still uncertain, it has been established that the presence of a nanocarbon can retard recombination of the photo-excited electrons and holes. The improved activity critically depends on the method of synthesis, which should be designed as to have the maximum C-metal oxide contact. Much research has been conducted on graphene and carbon nanotubes, but other carbon structures are slowly coming to surface. The vast majority of reports focuses on photo-degradation of organic contaminants, but application to energy related fields is becoming more and more popular. (C) 2016 Elsevier B.V. All rights reserved.