Role of graphitic carbon in g-C3N4 nanoarchitectonics towards efficient photocatalytic reaction kinetics: A review

The efficiency of photocatalytic water splitting, and CO2 conversion depend on the separation and transfer of charge carriers. Graphitic carbon components with decent conductivity can enhance the transport of the photoinduced charges in semiconductor heterostructures. As a typical visible-light-responsive photocatalyst, the application of graphitic carbon nitride (g-C3N4) is often limited by the relatively high recombination rate of photogenerated charge carriers. g-C3N4 has been a hot base material for constructing metals and semiconductors modified hetero-and homo-junctions for the application of solar-driven fuel production. Graphitic carbon components are the keys in enhancing the transport efficiency of photogenerated charge carriers in g-C3N4 based heterostructures. In this review, important aspects of the roles of graphitic carbon components in g-C3N4 based photocatalysts are discussed to provide paradigms for the advancement of these materials in photocatalytic water splitting and CO2 reduction. Moreover, graphitic carbon can serve as a coating material, or be in layer or nanotube forms, to be incorporated into heterostructure materials to affect the mobility of the charge carriers in Schottky junctions as well as in Z-scheme and S-scheme heterostructures. Important feature changes in g-C3N4 based photocatalysts after graphitic carbon incorporation as well as the progress and achievements in these composite photocatalyst materials in water splitting and CO2 reduction are summarized.