78989-43-2Relevant academic research and scientific papers
Carbon-containing nano-titania prepared by chemical vapor deposition and its visible-light-responsive photocatalytic activity
Kuo, Chien-Sheng,Tseng, Yao-Hsuan,Huang, Chia-Hung,Li, Yuan-Yao
, p. 93 - 100 (2007)
Ultraviolet and visible-light-responsive titania was synthesized and employed in the NOx photomineralization. A thermal decomposition reaction of titanium isopropoxide was carried out with a metal-organic chemical vapor deposition (MOCVD), enabling continuous production of TiO2 nanoparticles. Carbon-containing titanium dioxide with the anatase phase prepared at 500 °C under nitrogen atmosphere exhibited high photocatalytic activity for NO oxidation under visible-light illumination. Experimental results indicate that up to 48% removal of NOx can be achieved in a continuous flow type of reaction system under visible-light illumination (green LED). The chamber temperature in this MOCVD process plays an important role in lattice structure formation, and also affected TiO2 carbon content. The carbonaceous species on the TiO2 surface, shown by X-ray diffractometry (XRD), and Raman, UV-vis, and X-ray photoelectron spectroscopies (XPS), is important to the visible-light absorption and visible-light-catalytic mineralization of NOx.
ZIF-67/CoOOH cocatalyst modified g-C3N4 for promoting photocatalytic deep oxidation of NO
Du, Guangzhi,Huang, Zeai,Li, Bangxin,Wang, Dajun,Xiao, Wenyan,Yi, Zeyu,Zhang, Qian,Zhao, Hongtao,Zheng, Qian,Zhu, Lin,Zou, Yanzhao
supporting information, (2021/06/15)
The removal of nitrogen oxides (NOX) by semiconductor photocatalysis is an emerging technology in recent years. However, due to incomplete oxidation, the photocatalytic oxidation of NOX is usually accompanied by the generation of toxic intermediate by-products nitrogen dioxide (NO2), which causes secondary pollution and seriously limits its practical application. To tackle the issue, ZIF-67/CoOOH (ZIF-CH) cocatalyst was constructed via flexible strongly alkali oxidation treatment to modify g-C3N4, in which ZIF-67 was selected as a cobalt source of CoOOH. XRD, SEM, TEM and XPS demonstrated the ZIF-CH was successfully synthesized and anchored on CN. UV–vis, PL, EIS, transfer photocurrent response and DFT indicated that the introduction of ZIF-CH enlarged the response range to visible light, favored the separation and transfer of carriers and improved NO/NO2 adsorption ability. Consequently, the optimized ZIF-67/CoOOH/g-C3N4 (ZIF-CH/CN) exhibited a superior NO removal efficiency of 52.5% without any generation of toxic by-product NO2, and the cycling tests indicated the high stability of ZIF-CH/CN was obtained. In-suit DRIFTS and ESR were used to investigate the reaction pathway by comparing adsorption energy and detecting the reaction intermediates and products. More importantly, this result reveal that amount of hydroxyl radical (·OH) increased after introducing ZIF-CH cocatalyst, which promotes the deep oxidation of NO. These findings could supply a convenient and effective strategy for the design of a cocatalyst to enhance the photocatalytic oxidation performance of NO and inhibit the production of toxic by-product NO2.
Facile synthesis of double cone-shaped Ag4V2O7/BiVO4 nanocomposites with enhanced visible light photocatalytic activity for environmental purification
Hu, Yang,Fan, Jun,Pu, Chenchen,Li, Hua,Liu, Enzhou,Hu, Xiaoyun
, p. 172 - 183 (2017/02/18)
Ag4V2O7/BiVO4 photocatalysts with double cone-shaped nanostructure were successfully synthesized by a facile sodium polyphosphate-assisted hydrothermal method. The results demonstrate that coupling Ag4V2O7 with BiVO4 can promote the separation of photoinduced charge carriers and enhance the photon absorption efficiency. Experimental results indicate that Ag4V2O7/BiVO4 composites exhibit the enhanced photocatalystic activity for degradation of methylene blue (MB) and oxidation of NO in high concentrate (1600?ppb) compared to the pure BiVO4 under visible light irradiation (λ?>?420?nm). The composite with 0.08 mol% Ag4V2O7 has the highest photocatalytic activity. MB degradation rate can reach 98.48% in 1?h and NO oxidation rate can reach 52.83% in 0.5?h on 0.08-Ag4V2O7/BiVO4, which are about 2.90 and 3.11 times higher than that of pure BiVO4 respectively. The excellent activity can be attributed to the efficient charge transfer between Ag4V2O7 and BiVO4, and active species h+ and [rad]O2? play important roles during MB degradation and NO oxidation. In addition, this composite exhibits favorable stability during the cycling experiment, suggesting it may be a promising visible light active photocatalyst for environmental applications.
Absorption and Oxidation of Nitrogen Oxide in Ionic Liquids
Kunov-Kruse, Andreas J.,Thomassen, Peter L.,Riisager, Anders,Mossin, Susanne,Fehrmann, Rasmus
, p. 11745 - 11755 (2016/08/05)
A new strategy for capturing nitrogen oxide, NO, from the gas phase is presented. Dilute NO gas is removed from the gas phase by ionic liquids under ambient conditions. The nitrate anion of the ionic liquid catalyzes the oxidation of NO to nitric acid by atmospheric oxygen in the presence of water. The nitric acid is absorbed in the ionic liquid up to approximately one mole HNO3per mole of the ionic liquid due to the formation of hydrogen bonds. The nitric acid can be desorbed by heating, thereby regenerating the ionic liquid with excellent reproducibility. Here, time-resolved in-situ spectroscopic investigations of the reaction and products are presented. The procedure reveals a new vision for removing the pollutant NO by absorption into a non-volatile liquid and converting it into a useful bulk chemical, that is, HNO3.
Ferric microperoxidase-11 catalyzes peroxynitrite isomerization
Ascenzi, Paolo,Leboffe, Loris,Santucci, Roberto,Coletta, Massimo
, p. 56 - 61 (2015/01/30)
Microperoxidase-11 (MP11) is an undecapeptide derived from horse heart cytochrome c offering the possibility to study the reactivity of the heme group relatively unshielded by the protein. Here, the peroxynitrite isomerization to NO3-/sup
Natural kaolin derived stable SBA-15 as a support for Fe/BiOCl: A novel and efficient Fenton-like catalyst for the degradation of 2-nitrophenol
Zhao, Qihang,Liu, Xiaoyan,Sun, Menglin,Du, Chunfang,Liu, Zhiliang
, p. 36948 - 36956 (2015/05/05)
The ordered mesoporous material SBA-15 (FCSBA-15) with an enhanced hydrothermal stability was successfully synthesized from natural kaolin in the presence of a fluorocarbon surfactant. FCSBA-15 was further used as the support for Fe/BiOCl with the aim of exploring its Fenton-like catalytic performance toward the degradation of 2-nitrophenol. Based on characterization techniques including X-ray diffraction (XRD), transmission electron microscopy (TEM) and high-resolution TEM (HRTEM), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS), no phases referring to the Fe species were observed, suggesting that the Fe3+ ions may be present on the surface of flower-like BiOCl. It is noted that the Fe3+ ions could lead to a morphological reconstruction from BiOCl nanosheets to BiOCl flowers. The obtained Fe/BiOCl-FCSBA-15 exhibited an excellent degradation efficiency for 2-nitrophenol, which reached nearly 100% within 40 min by optimizing parameters such as the H2O2 dosage, pH value, temperature, Fe/Bi molar ratio and Bi/Si molar ratio. The finding reported here is important and may help to develop novel mesoporous matrix based systems for advanced catalysts.
In situ decoration of plasmonic Ag nanocrystals on the surface of (BiO)2CO3 hierarchical microspheres for enhanced visible light photocatalysis
Dong, Fan,Li, Qiuyan,Zhou, Ying,Sun, Yanjun,Zhang, Haidong,Wu, Zhongbiao
, p. 9468 - 9480 (2014/06/23)
Novel plasmonic 0D Ag nanocrystal decorated 3D (BiO)2CO 3 hierarchical microspheres were fabricated with a one-pot hydrothermal method. The as-prepared samples were systematically characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy, UV-vis diffuse reflectance spectroscopy, photoluminescence spectra, ns-level time-resolved fluorescence spectra, photocurrent generation and EIS measurement. The results indicated that the 0D Ag nanoparticles were deposited on the surface of 3D (BiO)2CO3 hierarchical microspheres. The deposited Ag nanoparticles were reduced from Ag+ by the citrate ions from bismuth citrate. The photocatalytic activity of the as-prepared samples was evaluated towards the degradation of NO at ppb-level under visible light irradiation. The intermediate NO2 was monitored on-line during the photocatalytic reaction. The pure (BiO)2CO 3 microspheres exhibited decent visible light photocatalytic activity because of the surface scattering and reflecting (SSR effect) resulting from the special 3D hierarchical architecture. The Ag-decorated (BiO) 2CO3 microspheres (Ag/BOC) exhibited greatly enhanced photocatalytic activity, photocurrent generation and promoted NO2 oxidation compared to the pure (BiO)2CO3 microspheres. The enhanced photocatalytic activity and photocurrent generation of Ag/BOC was ascribed to the cooperative contribution of the surface plasmon resonance (SPR effect), efficient separation of electron-hole pairs and prolonged lifetime of charge carriers induced by Ag nanoparticles. The photocatalytic performance of Ag/BOC was dependent on the content of Ag loading. When the amount of Ag is controlled at 5%, the highest photocatalytic performance can be achieved. Further increasing the Ag loading content promotes aggregation of the Ag particles and transforms the uniform microspheres into non-uniform microspheres, which is not beneficial to improving the activity. Importantly, the as-prepared Ag/BOC composites exhibited high photochemical stability after multiple reaction runs. The concepts of enhancing the activity through the SSR and SPR effects provide a new avenue for the development of efficient noble metal/bismuth-based plasmonic photocatalysts with attractive nano/micro architectures for efficient visible light photocatalytic activity.
Photodegradation of p-nitrophenol using octahedral Cu2O particles immobilized on a solid support under a tungsten halogen lamp
Zhai, Wei,Sun, Fengqiang,Chen, Wei,Pan, Zizhao,Zhang, Lihe,Li, Shaohua,Feng, Shuilan,Liao, Yiyi,Li, Weishan
, p. 59 - 65 (2013/08/25)
Octahedral Cu2O particles were prepared on an indium-tin oxide glass via electrodeposition and were employed in the catalytic degradation of p-nitrophenol in the presence of H2O2. Under irradiation of a warm visible-light source, tungsten halogen lamp, Cu2O particles not only acted as a photocatalyst, but might also act as a thermal-catalyst to induce the decomposition of H2O2 and produce O2 at higher temperatures. The photogenerated electrons and holes could react with H2O2, O2, and H2O to produce abundant OH radicals, resulting in the effective oxidation of p-nitrophenol. High-performance liquid chromatography measurements of degradation intermediates showed that p-nitrophenol was first decomposed into hydroquinone and benzoquinone and then mineralized. The degradation efficiency was dependent on electrodeposition time, light intensity, H2O2 amount, and solution temperature. This catalyst could be easily recycled and used in the efficient degradation of other phenolic compounds.
Observation of gas-phase peroxynitrous and peroxynitric acid during the photolysis of nitrate in acidified frozen solutions
Abida, Otman,Mielke, Levi H.,Osthoff, Hans D.
, p. 187 - 192 (2011/10/05)
The photolysis of nitrate embedded in ice and snow can be a significant source of volatile nitrogen oxides affecting the composition of the planetary boundary layer. In this work, we examined the nitrogen oxides evolved from irradiated frozen solutions containing nitrate. Products were monitored by cavity ring-down spectroscopy (CRDS), NO-O3 chemiluminescence (CL), and chemical ionization mass spectrometry (CIMS). Under acidic conditions, the nitrogen oxides volatilized were mainly in the form of NOz, i.e., nitrous (HONO), nitric (HONO2), peroxynitrous (HOONO), and peroxynitric acid (HO2NO2). Identification of acidic nitrogen oxides by CIMS and possible HOONO, HONO2 and HO 2NO2 formation pathways are discussed.
Kinetics of N2O5 hydrolysis on secondary organic aerosol and mixed ammonium bisulfate-secondary organic aerosol particles
Escorcia, Egda N.,Sjostedt, Steven J.,Abbatt, Jonathan P.D.
, p. 13113 - 13121 (2011/02/28)
The kinetics of the hydrolysis reaction of N2O5 on secondary organic aerosol (SOA) produced through the ozonolysis of α-pinene and on mixed ammonium bisulfate-SOA particles was investigated using an entrained aerosol flow tube coupled to a chemical ionization mass spectrometer. We report room temperature uptake coefficients, γ, on ammonium bisulfate and SOA particles at 50% relative humidity of 1.5 × 10-2 ± 1.5 × 10-3 and 1.5 × 10 -4 ± 2 × 10-5, respectively. For the mixed ammonium bisulfate-SOA particles, γ decreased from 2.6 × 10 -3 ± 4 × 10-4 to 3.0 × 10-4 ± 3 × 10-5 as the SOA mass fraction increased from 9 to 79, indicating a strong suppression in γ with the addition of organic material. There is an order-of-magnitude reduction in the uptake coefficient with the smallest amount of SOA material present and smaller additional reductions with increasing aerosol organic content. This newly coated organic layer may either decrease the mass accommodation coefficient of N 2O5 onto the particle or hinder the dissolution and diffusion of N2O5 into the remainder of the aerosol after it has been accommodated onto the surface. The former corresponds to a surface effect and the latter to bulk processes. The low value of the uptake coefficient on pure SOA particles will likely make N2O5 hydrolysis insignificant on such an aerosol, but atmospheric chemistry models need to account for the role that organics may play in suppressing the kinetics of this reaction on mixed organic-inorganic particles.
