Graphitic Carbon Nitride Isotype Heterostructures with Enhanced Visible Photocatalytic Properties

Abstract

In this work, highly active graphitic carbon nitride composite photocatalysts with an isotype heterojunction semiconductor structure have been prepared through the molecular composite precursors consisting of urea and melamine. These photocatalysts were characterized by XRD, SEM, TEM, UV-Vis, BET and transient photocurrent responses. The photodegradation of dyes in aqueous solution under visible-light irradiation has been investigated over carbon nitride photocatalysts consisting of different urea/melamine mass ratios. Further studies by photocurrent indicate that the photosynergistic effect of isotype heterojunction can remarkably enhance the photoinduced interfacial charge transfer, thereby increasing the charge separation during the photocatalytic reaction.

Cellulose-Derived Hierarchical g-C3N4/TiO2-Nanotube Heterostructured Composites with Enhanced Visible-Light Photocatalytic Performance

“…Figure a displays the nitrogen adsorption–desorption isotherms of the cellulose-derived 46%-g-C 3 N 4 /TiO 2 -NT nanocomposite, which shows a type IV adsorption isotherm accompanied by an H3 hysteresis loop ranging from 0.6 to 1.0 of the relative pressure ( P / P 0 ) according to the classification of IUPAC, suggesting the mesoporous structure of the nanocomposite. The value of the specific surface area derived from a Brunauer–Emmett–Teller (BET) model ( S BET ) of this nanocomposite is 62.1 m 2 g –1 , which exceeds the S BET of the g-C 3 N 4 matter (36.6 m 2 g –1 ) and the pure TiO 2 nanotubes (26.4 m 2 g –1 ) . The enhanced value of S BET of the cellulose-derived nanocomposite is assigned to the uniform dispersion of the g-C 3 N 4 layers onto the hierarchically network structured TiO 2 nanotube matrixes.…”