Construction of g-C₃N₄/S-g-C₃N₄ metal-free isotype heterojunctions with an enhanced charge driving force and their photocatalytic performance under anoxic conditions

Abstract

In the heterojunctions catalysts, the potential difference is the main driving force for efficient charge separation and transfer. The slight difference in the electronic band structure of the isotype heterojunctions catalysts causes the poor driving force, leading to the dissatisfactory charge separation 10 efficiency. In this work, g-C 3 N 4 /S-g-C 3 N 4 metal-free isotype heterojunctions catalysts (GCN-SCN) with the enhanced charge driving force were prepared by a two step calcination method. Anoxic photocatalytic degradation of RhB under visible light was used to evaluate the performance of as-prepared g-C 3 N 4 catalysts. The results indicate that this two step calcination method can markedly promote the charge driving force of as-prepared isotype heterojunctions, leading to the more efficient charge-carrier 15 migration. GCN-SCN displays the highest reaction rate constant of 0.0228 min -1 , which is 3.5 and 2.9 times higher than that of GCN/SCN(1) and GCN/SCN(2), prepared by one step calcination method. The linear relationship is observed between VB driving force and RhB degradation rate. This paper provides a new perspective to prepare the isotype heterojunctions with promoted charge driving force and photocatalytic performance.

Preparation of g-C3N4 with High Specific Surface Area and Photocatalytic Stability

“…87-1526. 15 These diffraction peaks can be attributed to the typical (100) and (002) lattice planes of g-C 3 N 4 and are consistent with previous reports on g-C 3 N 4 . 16 Moreover, the intensity of the diffraction peaks obviously increased with increasing calcination temperature.…”

“…Extensive efforts to improve the specific surface area of g-C 3 N 4 have already been reported; For example, Yan et al 14 prepared worm-like g-C 3 N 4 nanomaterial by using Pluronic P123 as a soft template, achieving a high specific surface area (90 m 2 /g) and good photocatalytic H 2 production (148.2 lmol/h). Wang et al 15 successfully synthesized mesoporous g-C 3 N 4 with a high specific surface area (373 m 2 /g) by using silica nanoparticles as a template, with the highest H 2 evolution rate being 149 lmol/h when the specific surface area was 67 m 2 /g. this means that the specific surface area is not proportional to the hydrogen production efficiency.…”

Promotion of activation ability of N vacancies to N2 molecules on sulfur-doped graphitic carbon nitride with outstanding photocatalytic nitrogen fixation ability

“…The binding energies for SCN and VN-SCN are located at 163.8 eV, which is attributable to the doping sulfur in the form of the S-C bond, as shown in Fig. 5 [33,34]. [35], all the samples are theoretically feasible for the photocatalytic reduction of N2 to NH4 + .…”

Influence of Solvothermal Post-Treatment on Photochemical Nitrogen Conversion to Ammonia with g-C₃N₄ Catalyst

“…The more negative reduction potential causes the larger CB driving force. This CB driving force determines the migration rate of photogenerated holes and electrons, causing the higher N2 photofixation ability 47 . Fig.8 shows the PL spectra of as-prepared catalysts under N2 atmosphere.…”