Carbon Nitride Quantum Dots Modified TiO2 Inverse Opal Photonic Crystal for Solving Indoor VOCs Pollution

Abstract

Indoor toxic volatile organic compounds (VOCs) pollution is a serious threat to people’s health and toluene is a typical representative. In this study, we developed a composite photocatalyst of carbon nitride quantum dots (CNQDs) in situ-doped TiO2 inverse opal TiO2 IO for efficient degradation of toluene. The catalyst was fabricated using a sol-gel method with colloidal photonic crystals as the template. The as-prepared catalyst exhibited excellent photocatalytic performance for degradation of toluene. After 6 h of simulated sunlight irradiation, 93% of toluene can be converted into non-toxic products CO2 and H2O, while only 37% of toluene is degraded over commercial P25 in the same condition. This greatly enhanced photocatalytic activity results from two aspects: (i) the inverse opal structure enhances the light harvesting while providing adequate surface area for effective oxidation reactions; (ii) the incorporation of CNQDs in the framework of TiO2 increases visible light absorption and promotes the separation of photo-generated charges. Collectively, highly efficient photocatalytic degradation of toluene has been achieved. In addition, it can be expanded to efficient degradation of organic pollutants in liquid phase such as phenol and Rhodamine B. This study provides a green, energy saving solution for indoor toxic VOCs removal as well as for the treatment of organic wastewater.

Carbon nitride quantum dots‐modified cobalt phosphate for enhanced photocatalytic H2 evolution

“…According to Figure 5A, C, N, O, P and Co elements were detected in CNQDs/CoPi‐2, and the atomic ratio of N:P:Co = 1.24:10.53:15.25, displaying that the content of CNQDs in CNQDs/CoPi‐2 composites is 1.56 wt%. The C1s spectrum (Figure 5B) can be deconvoluted into three peaks, the peak at 284.6 eV could belong to C–C bond, 34 the peak at 285.4 eV could be attributed to the sp2 C from C–N or C–O bonds 41 . The peak at 288.6 eV is related to the sp3 C from C–N bonds 42 .…”

“…The C1s spectrum (Figure 5B) can be deconvoluted into three peaks, the peak at 284.6 eV could belong to C-C bond, 34 the peak at 285.4 eV could be attributed to the sp2 C from C-N or C-O bonds. 41 The peak at 288.6 eV is related to the sp3 C from C-N bonds. 42 The N 1s spectrum (Figure 5C) is deconvoluted into three peaks with the center at 398.3, 399.3, and 400.7 eV, which could be explained as the C=N-C, C-N-C, N-(C) 3 groups, respectively.…”

Research and Application Progress of Inverse Opal Photonic Crystals in Photocatalysis

“…This method is suitable for the filling of most semiconductor oxide materials, but the filling rate is not high, and the volume shrinkage after drying is large. Some researchers have used the sol-gel method to prepare inverse opal photonic crystal photocatalysts [55][56][57]. Jie Yu [55] developed an inverse opal titanium dioxide photonic crystal photocatalyst to effectively degrade toluene.…”

Recent Progress of Carbon Dots for Air Pollutants Detection and Photocatalytic Removal: Synthesis, Modifications, and Applications

“…According to the report from Yu et al., they prepared N‐CDs/TiO 2 nanomaterials for photodegradation toluene, which exhibited a mineralization rate of 93% under simulated sunlight irradiation for 6 h, while that of commercial photocatalyst TiO 2 (P25) was just 37%. [ 214 ] In another report, novel photocatalysts of CDs/BiOCl exhibited nearly three times the toluene mineralization efficiency of pristine BiOCl. [ 215 ] The authors used theoretical calculations to investigate the adsorption process of toluene oxidation intermediates on different photocatalysts’ surfaces.…”