Recent advances of nanocarbon-inorganic hybrids in photocatalysis

Fullerenes, carbon nanotubes, and graphene, among other nanocarbon allotropes, have been the subject of intense research as cocatalysts with semiconductors in heterogeneous photocatalysis in the last two decades. Their unique properties, such as high specific surface area, excellent electric conductivity, and valuable thermal and chemical stability, combined with those of semiconductors lead to a synergy giving rise to a better photocatalytic performance. Hence, nanocarbon-semiconductor hybrids (NSH) can be considered cheap and efficient options as cocatalysts, compared to the use of noble metals. In most cases, the photocatalytic properties of NSHs are influenced by the preparation method, size, morphology, and chemical composition, which impacts the nature and extent of interfacial charge and energy transfer between the two components. After all, the nanocarbon-semiconductor interaction leads to a more considerable photoactivity, controlled selectivity, and high stability that is attributed to superior adsorption of reactants, a broader absorption range of light wavelengths, and extinguished recombination of photogenerated charge-carriers. However, despite a significant amount of work published on this topic, the fundamental aspects and mechanisms by which photocatalytic reactions occur have not been entirely unraveled.