Modification of Graphitic Carbon Nitride with Hydrogen Peroxide

Abstract

Graphitic carbon nitride (GCN) was synthetized by heating melamine and then it was thermally exfoliated for 1–3 h in air. Both bulk and exfoliated GCN nanomaterials were treated in the 10–30% aqueous solutions of H2O2 for us to study their modification. The light absorption properties were observed by the reddish color and the red-shifts of their UV-Vis spectra. The content of oxygen increased and hydrogen peroxide was supposed to partially oxidize C-OH groups to C=O ones and to form C-O-C groups instead of edge C-NH-C ones. The GCN structure changes were not observed. However, a surface modification of the GCN materials was recognized by their changed photocatalytic activities tested by means of Acid Orange 7 (AO7) and Rhodamines B (RhB), zeta-potentials, and neutralization titration curves.

Electrostatic interaction mechanism of visible light absorption broadening in ion-doped graphitic carbon nitride

“…Thus, according to TGA-MS data, the control experiments and the FTIR results, a proposed structure of CN-K-OOH is displayed in Scheme 2 from both top and side view. It is suggested that the electrostatic attraction between K + and OOH À as well as the intermolecular hydrogen bond inside CN-K-OOH would cause the charge redistribution of CN-K-OOH to enhance its visible light absorption, which is different from the proposed O-doping mechanism in H 2 O 2 hydrothermal treatment of pristine CN, [15][16][17][18][19][20][21] and also different from the suggested cationdetermining mechanism in previous reports. 22,23 The present experimental results call for support from theoretical simulation work.…”

“…[12][13][14] In the case of Odoping, a H 2 O 2 hydrothermal treatment of pristine CN was usually carried out, where H 2 O 2 is used to generate oxygencontaining groups so as to modulate the electronic conguration of O-doped CN. [15][16][17][18][19][20][21] In 2019, Ge et al reported a simple H 2 O 2 treatment of Li-doped CN, and the obtained product shows a light absorption extending up to 650 nm. 22 However, Li atom doping into CN was suggested to be responsible for the optical property change.…”

Carbon Nitride-Based Catalysts for High Pressure CO2 Photoreduction

“…Indeed, TiO2exCl is mainly composed of the anatase phase, and it lacks long range crystallinity, as evidenced by the broad and low intensity reflections. The two main diffraction peaks for C3N4-TE at 13° and 27°, reported in Figure 1b, can be attributed to the (100) and (002) crystallographic planes of the material [27]. As reported in literature, the intensity of the main diffraction peak of C3N4 is very low when it is coupled with titania, due to the high crystallinity of P25 [28].…”

“…[26]. C 3 N 4 is characterized by a graphitic 2D type structure [27] and, despite its moderate activity due to the high electron/hole recombination rate, the photocatalytic properties can be improved by chemical, mechanical, or thermal exfoliation, so the graphiticlike planes are exposed and functionalized [27]. Calcination is a successful methodology to obtain high surface area C 3 N 4 nanosheets (thermal exfoliation, TE).…”