Pilot-Scale Studies of WO3/S-Doped g-C3N4 Heterojunction toward Photocatalytic NOx Removal

Abstract

Due to the rising concentration of toxic nitrogen oxides (NOx) in the air, effective methods of NOx removal have been extensively studied recently. In the present study, the first developed WO3/S-doped g-C3N4 nanocomposite was synthesized using a facile method to remove NOx in air efficiently. The photocatalytic tests performed in a newly designed continuous-flow photoreactor with an LED array and online monitored NO2 and NO system allowed the investigation of photocatalyst layers at the pilot scale. The WO3/S-doped-g-C3N4 nanocomposite, as well as single components, were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller surface area analysis (BET), X-ray fluorescence spectroscopy (XRF), X-ray photoemission spectroscopy method (XPS), UV–vis diffuse reflectance spectroscopy (DR/UV–vis), and photoluminescence spectroscopy with charge carriers’ lifetime measurements. All materials exhibited high efficiency in photocatalytic NO2 conversion, and 100% was reached in less than 5 min of illumination under simulated solar light. The effect of process parameters in the experimental setup together with WO3/S-doped g-C3N4 photocatalysts was studied in detail. Finally, the stability of the composite was tested in five subsequent cycles of photocatalytic degradation. The WO3/S-doped g-C3N4 was stable in time and did not undergo deactivation due to the blocking of active sites on the photocatalyst’s surface.

Self-Powered Photoelectrochemical Photodetectors Based on a CsPbBr3/S-g-C3N4 Heterojunction-Sensitized 3D ZnO Nanostructured Thin Film

“…This defect-based emission signal disappeared with the S- g -C 3 N 4 layer due to the increase in the PL intensity (Figure S4d). The PL spectra of S- g -C 3 N 4 depict a characteristic broad peak starting from ∼450 to ∼550 nm . Therefore, the formation of a small PL signal was observed at 450 nm belonging to the S- g -C 3 N 4 layer.…”

“…The PL spectra of S-g-C 3 N 4 depict a characteristic broad peak starting from ∼450 to ∼550 nm. 53 Therefore, the formation of a small PL signal was observed at 450 nm belonging to the S-g-C 3 N 4 layer. The perovskite materials are sensitive to open air conditions such as oxygen and humidity, which led to a restriction on their use in practical applications.…”

Recent Advances in Carbon Nitride-Based S-scheme Photocatalysts for Solar Energy Conversion

“…Therefore, it is difficult to achieve a broad spectral response and strong redox capabilities in pure carbon nitride [ 39 , 40 ]. Multi-component heterojunction photocatalysts offer unique advantages over single-component photocatalysts in terms of the charge separation [ 41 , 42 , 43 , 44 , 45 ]. According to the equation of the coulomb force: F c = kq e q h /r 2 , heterojunction photocatalysts can realize the spatial separation of photogenerated carriers, increase the distance between electrons and holes, and reduce the coulomb force between them, thus inhibiting the recombination of photogenerated carriers [ 46 ].…”

Synthesis of Ag3PO4/Ag/g-C3N4 Composite for Enhanced Photocatalytic Degradation of Methyl Orange

“…In addition, the micro-solubility of Ag 3 PO 4 will reduce its structural stability. Therefore, it is a serious challenge to develop a highly efficient composite photocatalytic activity that maintains the stability of Ag 3 PO 4 [ 15 , 16 ].…”