The quantum yield is an important factor to evaluate the efficiency of photoreactor. This article gives an overall calculation method of the quantum efficiency( Φ ) and the apparent quantum efficiency( Φ a) to...The quantum yield is an important factor to evaluate the efficiency of photoreactor. This article gives an overall calculation method of the quantum efficiency( Φ ) and the apparent quantum efficiency( Φ a) to the TiO 2/UV photocatalysis system. Furthermore, for the immobility system (IS), the formulation of the faction of light absorbed by the TiO 2 thin film is proposed so as to calculate the quantum efficiency by using the measured value and theoretic calculated value of transmissivity (T). For the suspension system(SS), due to the difficulty to obtain the absorption coefficient ( α ) of TiO 2 particulates, the quantum efficiency is calculated by means of the relative photonic efficiency ( ζ r) and the standard quantum yield ( Φ standard ).展开更多
Understanding the structural changes and degradation mechanisms of organic pollutants is critical in environmental research.In this work,a xenon lamp was used as an analog light source to simulate the effect of sunlig...Understanding the structural changes and degradation mechanisms of organic pollutants is critical in environmental research.In this work,a xenon lamp was used as an analog light source to simulate the effect of sunlight on 3,3′-diamino-4,4′-azoxyfurazan(DAAF)in aqueous solution.Combining high-performance liquid chromatography coupled with tandem mass spectrometry(HPLC–MS/MS),surface-enhanced Raman spectroscopy(SERS)with density functional theory(DFT),the degradation intermediates and mechanisms of DAAF were investigated.The sequential breakdown of the–NH2 and–O–N=bonds,followed by the removal of atomic O from–N=N(O)–,was emphasized and investigated using two-dimensional correlation spectroscopy(2D-COS)and SERS spectra.Three intermediates with mass-to-charge ratios(m/z)181,251 and 180 were identified and characterized by integrating experimental SERS data with DFT-calculated Raman spectra based on structures hypothesized from MS spectra.The findings from HPLC–MS and SERS not only corroborate each other but also provide a foundation for a detailed examination of the DAAF degradation process.展开更多
A series of new photodegradable poly(furan-amine)s(PFAs) were synthesized by a one-pot, catalyst-free, multicomponent cyclopolymerization between diisocyanides, dialkylacetylene dicarboxylates, and aromatic dialdehyde...A series of new photodegradable poly(furan-amine)s(PFAs) were synthesized by a one-pot, catalyst-free, multicomponent cyclopolymerization between diisocyanides, dialkylacetylene dicarboxylates, and aromatic dialdehydes. All polymerizations were conducted in toluene at 100 ℃ for 6 h without inert gas protection and furnished polymers with a satisfactory molecular weight(Mw up to32200) and yield. The PFA structure was confirmed by spectroscopic techniques, such as GPC, FTIR, and NMR, as well as by comparison with a model compound. The polymers exhibited good solubility in common organic solvents and thermal stability. All the PFAs had high refractive indices in the visible light region(400 nm to 800 nm). Moreover, the PFAs were substantially degraded by UV irradiation due to the presence of furan rings. The film thickness reduction rate could be over 90%.展开更多
Cobalt oxide doped titanate nanotubes are synthesized with a simple hydrothermal treatment of mixed Co3O4 and TiO2 powders. The formed tubular nanostructure, chemical composition,and the elemental distribution are ana...Cobalt oxide doped titanate nanotubes are synthesized with a simple hydrothermal treatment of mixed Co3O4 and TiO2 powders. The formed tubular nanostructure, chemical composition,and the elemental distribution are analyzed using TEM, BET, FTIR, XRD, and XPS. The electrocatalytic activity towards oxygen evolution reactions and photodegradation against Rhodamine B are investigated. It has been found out that the oxygen evolutions starts at 0.8 V and reaches 0.98 mA ·cm^-1 at 1.4 V vs. SCE. For photodegradation of Rhodamine B, the concentration decreased to 24% after 1 h irradiation using the sample with a mass percentage of 5% cobalt. The results demonstrate that the cobalt oxide doped titanate nanotubes are good candidates as electrocatalysts and photocatalytic materials.展开更多
文摘The quantum yield is an important factor to evaluate the efficiency of photoreactor. This article gives an overall calculation method of the quantum efficiency( Φ ) and the apparent quantum efficiency( Φ a) to the TiO 2/UV photocatalysis system. Furthermore, for the immobility system (IS), the formulation of the faction of light absorbed by the TiO 2 thin film is proposed so as to calculate the quantum efficiency by using the measured value and theoretic calculated value of transmissivity (T). For the suspension system(SS), due to the difficulty to obtain the absorption coefficient ( α ) of TiO 2 particulates, the quantum efficiency is calculated by means of the relative photonic efficiency ( ζ r) and the standard quantum yield ( Φ standard ).
基金supported by the Research Fund of SWUST for Ph.D. (22zx7175)the Sichuan Science and Technology Program (24NSFSC5122)
文摘Understanding the structural changes and degradation mechanisms of organic pollutants is critical in environmental research.In this work,a xenon lamp was used as an analog light source to simulate the effect of sunlight on 3,3′-diamino-4,4′-azoxyfurazan(DAAF)in aqueous solution.Combining high-performance liquid chromatography coupled with tandem mass spectrometry(HPLC–MS/MS),surface-enhanced Raman spectroscopy(SERS)with density functional theory(DFT),the degradation intermediates and mechanisms of DAAF were investigated.The sequential breakdown of the–NH2 and–O–N=bonds,followed by the removal of atomic O from–N=N(O)–,was emphasized and investigated using two-dimensional correlation spectroscopy(2D-COS)and SERS spectra.Three intermediates with mass-to-charge ratios(m/z)181,251 and 180 were identified and characterized by integrating experimental SERS data with DFT-calculated Raman spectra based on structures hypothesized from MS spectra.The findings from HPLC–MS and SERS not only corroborate each other but also provide a foundation for a detailed examination of the DAAF degradation process.
基金financially supported by the National Natural Science Foundation of China (Nos. 21490574, 21875019, 51673024, and 51803009)Beijing Institute of Technology Research Fund Program for Young Scholars
文摘A series of new photodegradable poly(furan-amine)s(PFAs) were synthesized by a one-pot, catalyst-free, multicomponent cyclopolymerization between diisocyanides, dialkylacetylene dicarboxylates, and aromatic dialdehydes. All polymerizations were conducted in toluene at 100 ℃ for 6 h without inert gas protection and furnished polymers with a satisfactory molecular weight(Mw up to32200) and yield. The PFA structure was confirmed by spectroscopic techniques, such as GPC, FTIR, and NMR, as well as by comparison with a model compound. The polymers exhibited good solubility in common organic solvents and thermal stability. All the PFAs had high refractive indices in the visible light region(400 nm to 800 nm). Moreover, the PFAs were substantially degraded by UV irradiation due to the presence of furan rings. The film thickness reduction rate could be over 90%.
基金Supported by the National Natural Science Foundation of China(21576216,51372192)the Innovation Foundation from China Southern Power Grid(GDKJQQ20152050)
文摘Cobalt oxide doped titanate nanotubes are synthesized with a simple hydrothermal treatment of mixed Co3O4 and TiO2 powders. The formed tubular nanostructure, chemical composition,and the elemental distribution are analyzed using TEM, BET, FTIR, XRD, and XPS. The electrocatalytic activity towards oxygen evolution reactions and photodegradation against Rhodamine B are investigated. It has been found out that the oxygen evolutions starts at 0.8 V and reaches 0.98 mA ·cm^-1 at 1.4 V vs. SCE. For photodegradation of Rhodamine B, the concentration decreased to 24% after 1 h irradiation using the sample with a mass percentage of 5% cobalt. The results demonstrate that the cobalt oxide doped titanate nanotubes are good candidates as electrocatalysts and photocatalytic materials.
