Synthesis of Nanocrystalline Photo-Active Semiconductors

Graphitic carbon nitride nanotubes: a new material for emerging applications

“…As photoactive, visible-light sensitive, and photostable semiconductor, GCN has been broadly studied as a photocatalyst in a variety of redox-processes with a special focus on those constituting the realm of artificial photosynthesis , that is, the photocatalytic water splitting to H 2 and O 2 , or the reduction to hydrogen by electron donors, 16–18,27,30–36,40,155 CO 2 conversion to CO and hydrogenated fuels (CH 3 OH, CH 4 ), 16,17,27,31,37,156,157 nitrogen reduction, 19,157 as well as generation of photocurrent in photoelectrochemical systems. 18,30,31,36,38,49,51…”

“…The GCNTs produced by scrolling and modified with Rh NCs were reported as a visible-light-sensitive photocatalyst of dechlorination of mono-, di-, and tri-substituted chlorophenols into the corresponding alcohols and ketones in aqueous solutions saturated with molecular hydrogen. 134 In contrast to the more conventional photocatalytic destruction of substituted phenols proceeding through the hydroxylation, subsequent opening of the aromatic rings, and the formation of a mixture of oxycarboxylic acids, 50,51 the reported process allows the homogeneous dissociation of C–halogen bonds on the surface of Rh NCs to be achieved and coupling of Cl and phenol radicals with hydrogen atoms to form HCl and hydrogenated alcohols and ketones with a selectivity reaching 80–90%. 134…”

“…12,15,16,29,43 In the case of “conventional” inorganic semiconductors, these limitations could be defeated by assembling nanocrystalline semiconductors into mesoporous materials with high surface area as well as by designing single crystals or nanocrystal assemblies with anisotropic shape, including nanorods, nanowires, nanosheets, nanotubes, and hollow spheres, where a directed charge carrier migration can be achieved and electron–hole recombination successfully avoided. 50,51 These approaches were found to be applicable and very fruitful also for GCN. 12,15–17,21,27,29–35,38,43,47,48,52 An additional dimension in the design of the GCN-based photocatalytic systems was introduced by the inherent layered structure of GCN, which is formed by ππ-stacked atomically-thick aromatic layers of infinite networks of heptazine (tri- s -triazine) or triazine heterocycles.…”