In this study, a chemical precipitation approach was adopted to produce a photocatalyst based on bismuth tungstate Bisub.2WOsub.6 for enhanced and environmentally friendly organic pollutant ...degradation. Various tools such as X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), optical spectroscopy and X-ray photoelectron spectroscopy, were employed to assess the structural and morphological properties. Hence, the XRD profiles showed a well crystallized Bisub.2WOsub.6 orthorhombic phase. The photocatalytic performance of the resulting photocatalyst was assessed by the decomposition of Rhodamine B (RhB) and methyl orange (MO) with a decomposition efficiency of 97 and 92%, along with the highest chemical oxygen demand of 82 and 79% during 120 min of illumination, respectively. The principal novelty of the present work is to focus on the changes in the crystalline structure, the morphology, and the optical and the photoelectrochemical characteristics of the Bisub.2WOsub.6, by tuning the annealing temperature of the designed photocatalyst. Such physicochemical property changes in the as-prepared photocatalyst will affect in turn its photocatalytic activity toward the organic pollutant decomposition. The photocatalytic mechanism was elaborated based on electrochemical impedance spectroscopy, photocurrent analysis, photoluminescence spectroscopy, and radical trapping measurements. The overall data indicate that the superoxide Osub.2 sup.•− and holes hsup.+ are the principal species responsible for the pollutant photodegradation.
Catalyst-loaded activated carbons are the widely used adsorbents to remove H.sub.2S for purification of the gas streams. Virgin carbon, single, and mixed catalyst-loaded carbon are used as ...adsorbents. Their performance of H.sub.2S catalytic conversion was studied by evaluating their breakthrough curves in order to investigate the effect of catalyst contents, categories, assistant catalysts, and virgin carbon properties on the H.sub.2S adsorption. The effects of gas stream properties on H.sub.2S catalytic adsorption are also investigated. The results show the H.sub.2S u amount is increased with catalyst contents, and the assistant catalysts can enhance H.sub.2S catalytic conversion. NaOH-loaded carbon has better catalytic performance than KOH-loaded carbon with the same contents. Carbons after impregnation keep a relative high-pore volume between 2 and 20 nm, which is beneficial to give full play to the catalysis. The relative humidity and oxygen can enhance the H.sub.2S adsorption capacity and play important roles in H.sub.2S adsorption. CTC has little effects on the impregnated carbon for H.sub.2S catalytic conversion. Carbon impregnated with a specific catalyst can accelerate target substance adsorption and will restrict the pore volume for organics adsorption.
Sulfamates are widespread in numerous pharmacologically active molecules. In this paper, Silver/Bathophenanthroline catalyzed the intramolecular selective amination of primary C(spsup.3)−H bonds and ...secondary C(spsup.3)−H bonds of sulfamate esters, to produce cyclic sulfamates in good yields and with a high site-selectivity. DFT calculations revealed that the interaction between sulfamates and L10 makes the molecule more firmly attached to the catalyst, benefiting the catalysis reaction. The in vitro anticancer activity of the final products was evaluated in MCF-7 breast cancer cells.
Transforming COsub.2 into value-added chemicals has been an important subject in recent years. The development of a novel heterogeneous catalyst for highly effective COsub.2 conversion still remains ...a great challenge. As an emerging class of porous organic polymers, covalent organic frameworks (COFs) have exhibited superior potential as catalysts for various chemical reactions, due to their unique structure and properties. In this study, a layered two-dimensional (2D) COF, IM4F-Py-COF, was prepared through a three-component condensation reaction. Benzimidazole moiety, as an ionic liquid precursor, was integrated onto the skeleton of the COF using a benzimidazole-containing building unit. Ionization of the benzimidazole framework was then achieved through quaternization with 1-bromobutane to produce an ionic liquid-immobilized COF, i.e., BMIM4F-Py-COF. The resulting ionic COF shows excellent catalytic activity in promoting the chemical fixation of COsub.2 via reaction with epoxides under solvent-free and co-catalyst-free conditions. High porosity, the one-dimensional (1D) open-channel structure of the COF and the high catalytic activity of ionic liquid may contribute to the excellent catalytic performance. Moreover, the COF catalyst could be reused at least five times without significant loss of its catalytic activity.
RuO.sub.2/TiO.sub.2 catalysts with different TiO.sub.2 crystal sizes were prepared via a dry impregnation method, and these prepared catalysts were applied in the oxidation of HCl. The results show ...that decreasing the support-crystal size is an effective method to enhance the dispersion of RuO.sub.2 on TiO.sub.2, which is helpful to increase the catalytic activity significantly. Graphic
Photo-thermo-catalytic or PTC purification of process gasses (i.e., air, flue gases, and others) from NOsub.x is presented in this study. A discussion of temperature’s role in photocatalytic NOsub.x ...removal and the progress of photo-thermo-catalytic reactors for the NOsub.x removal process are presented. Lab- and pilot-scale reactors are described. The impact of temperature on the photocatalytic conversion of hydrocarbons is analyzed with regard to its relation to the photocatalytic selective reduction of NOsub.x (photo-SCR). Another important issue is light transfer in pilot-scale reactors due to the sensitivity of light sources to temperature. Examples of light transfer solutions in photo-thermo-catalytic reactors are presented. Finally, the further development of photo-thermo-catalytic reactors is discussed, including pressurized systems.
It has been reported that beta-MnO.sub.2 has photocatalytic activity for the oxidative-coupling of 2-naphthols into 1,1'-bi-2-naphthols. Nevertheless, it is hard to exclude the possibility that the ...oxidative-coupling of 2-naphthols is initiated by beta-MnO.sub.2 catalysis in dark due to the insufficient investigations in the related reports. In the present work, the oxidative-coupling of 2-naphthols into 1,1'-bi-2-naphthols with different phases MnO.sub.2 catalysis in dark and under visible-light irradiation were systematically investigated. The results revealed that the oxidative-coupling of 2-naphthols is jointly initiated by MnO.sub.2 catalysis and O.sub.2-oxidation, not by MnO.sub.2 photocatalysis. Among the alpha-MnO.sub.2, beta-MnO.sub.2, gamma-MnO.sub.2 and delta-MnO.sub.2 catalysis, beta-MnO.sub.2 catalysis has the optimal performance, its selectivity for the oxidative-coupling of 2-naphthols into 1,1'-bi-2-naphthols is close to 100%, and its catalytic capacity could be well retained after multiple using. Our findings provide comprehensive and accurate understanding the catalytic role of MnO.sub.2 for the oxidative-coupling of 2-naphthols into 1,1'-bi-2-naphthols. Graphic In the present work, the oxidative-coupling of 2-naphthols into 1,1'-bi-2-naphthols was proved to be jointly initiated by MnO.sub.2 catalysis and O.sub.2-oxidation, not by MnO.sub.2 photocatalysis. beta-MnO.sub.2 has the optimal catalytic activity for the oxidative-coupling of 2-naphthols relative to alpha-MnO.sub.2, gamma-MnO.sub.2 and delta-MnO.sub.2.
Carbon nitride MXene exhibits good metal conductivity, high photothermal conversion, carrier mobility, and high exposure of active sites, which makes it a promising co-catalyst for photothermal ...synergistic transformation of COsub.2. In this paper, Tisub.3CN/TiOsub.2 heterojunction was constructed in situ using Tisub.3CN as TiOsub.2 precursor to investigate the performance of Tisub.3CN MXene in photothermal synergistic transformation of COsub.2, and then the monolayer structure was utilized to enhance the interfacial charge transfer and improve the photothermal catalytic activity of Tisub.3CN. The catalysts were characterized by SEM, XRD, XPS, and UV-Vis DRS, and it was found the heterojunction constructed by monolayer MXene had a narrower bandgap and a higher carrier generation mobility, which, combined with the catalytic activity test, proved the single monolayer Tisub.3CN MXene had better photothermal synergistic conversion efficiency of COsub.2, and the heterojunction yield was 11.36 μmol·gsup.−1·hsup.−1 after layering, compared with that before layering (9.41%), which was 1.2 times higher than that before layering (9.41 μmol·gsup.−1·hsup.−1).
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