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To enhance PM2.5 capture performance of a wire-cylinder electrostatic precipitator (ESP), magnetic field was introduced into ESP, and a mathematical model with multi-field coupling effect between gas flow field, electromagnetic field, and particle dynamical field was built. PM2.5 collection efficiency in ESP was simulated using computational fluid dynamics and Fluent software. Under the consideration of diffusion charge, the influence of applied magnetic field on PM2.5 collection efficiency at different working voltages and flue gas velocities was discussed. The research results indicate that no matter what operating parameters, the introduction of magnetic field obviously improves the capture performance of wire-cylinder ESP. The PM2.5 capture performance in magnetic field environment is better in the condition of higher working voltage and/or lower flue gas velocity. Furthermore, the capture effect of applied magnetic field on PM2.5 increases with the increase of flue gas velocity or the decrease of working voltage. The related results can provide references for researchers aiming at equipment modification and technological innovation of traditional ESP. [ABSTRACT FROM AUTHOR]

Z-Scheme MoS2/g-C3N4 heterojunction photocatalysts were fabricated using a hydrothermal deposition procedure together with a calcination route, and then applied for CO2 photoreduction. Experimental results indicated that the 10% MoS2/g-C3N4 heterojunction displayed the best photocatalytic performance. Furthermore, the maximum CO yields of 58.59 μmol (g-cat)−1 under 7 h-visible light irradiation was up to 2.94 times that of the unadulterated g-C3N4. The enhanced photocatalytic performance of 10% MoS2/g-C3N4 catalyst was due to the favored visible light response, the efficient separation of photogenerated electron–hole pairs as well as its larger specific surface area. [ABSTRACT FROM AUTHOR]

Mn-TiO2 catalysts were utilized as an ozonation catalyst for the first time to study the simultaneous catalytic ozonation of Hg0 and NO at low flue gas temperatures. BET, SEM-EDS, XRD, XPS, H2-TPR, NOx-TPD and Hg0-TPD were used to characterize the catalysts. The Mn-TiO2 catalyst, in which the molar content of metal Mn was 60%, exhibited the best catalytic activities of Hg0 and NO oxidation, compared with other Mn-TiO2 catalysts. It was found that within the range of experiment, the catalytic ozonation efficiency of Hg0 and NO was higher than that of ozonation or catalytic oxidation. The results also showed that the presence of NO gas inhibited the catalytic ozonation of elemental mercury, and the inhibition was enhanced with the NO inlet concentration, while few elemental mercury molecules did promote the catalytic ozonation of NO. The addition of H2O vapor promoted the catalytic ozonation of Hg0 and NO. In addition, 0.6Mn-TiO2 catalyst demonstrated a good TOS and cyclic stability. The catalytic ozonation of NO and Hg0 on Mn-TiO2 catalyst likely followed the Langmuir-Hinshelwood mechanism, where the hydroxyl radicals reacted with adjacently adsorbed NO molecules and elemental mercury on catalyst surface. [ABSTRACT FROM AUTHOR]

Fe was used as the modifier to improve the performance of CeZr2Ox catalyst for the selective catalytic reduction (SCR) reaction with ammonia. Experimental results revealed that proper Fe species (Fe/Ce molar ratio = 2) could effectively improve the SCR activity of CeZr2Ox, along with the elevated resistance to SO2 and H2O. The characterization results including BET, XRD, H2-TPR and NH3-TPD confirmed that Fe species in Fe2CeZr2Ox catalyst could inhibit the formation of ZrO2 crystals and lead to higher reducibility and surface acidity. In addition, more Ce3+ and surface active oxygen species could be detected on Fe2CeZr2Ox compared with CeZr2Ox. By means of in situ DRIFT technique, it could be deduced that the SCR reaction process over Fe2CeZr2Ox was accelerated mainly through theL-H pathway due to the advanced adsorption of NH3 and NOx species, along with the promoted NO conversion to NO2. Therefore, the modification of CeZrOx catalyst by Fe had a significant stimulation effect on its low-temperature SCR performance. [ABSTRACT FROM AUTHOR]

It was well recognized that Pb had a poisoning effect on a SCR catalyst. In this study, the deactivation mechanism of Pb on the Ce/TiO2 catalyst was investigated based on the characterization results of TPD and in situ DRIFT studies. It was found that the addition of Pb on the Ce/TiO2 catalyst not only inhibited the adsorption and activation of NH3 species, but also led to the decrease of the activity of adsorbed NH3 species in the SCR reaction. The adsorption of NOx species and the oxidation of NO by O2 over the Ce/TiO2 catalyst were also suppressed by the addition of Pb, while the reactivity of adsorbed NO2 species did not decrease. Moreover, the results revealed that the NH3-SCR reaction over the Ce/TiO2 catalyst followed both the E–R and L–H mechanisms, while the NH3-SCR reaction over Ce/TiO2-Pb was mainly controlled by the L–H mechanism. The contributions of the L–H mechanism to the SCR reactions over Ce/TiO2 and Ce/TiO2-Pb decreased with increasing reaction temperature. The deactivation of Ce/TiO2-Pb was mainly attributed to the suppressed NH3 adsorption and activation, accompanied by the inhibited NO oxidation and the decrease of Brønsted acid sites. [ABSTRACT FROM AUTHOR]

The extensive use of fossil fuels in residential and industrial fields has resulted in massive emission of gaseous pollutants, which poses a severe threat to the environment and human health. Consequently, it is critical to develop affordable air cleaning technology, catalytic oxidation is one of the most promising technologies for this purpose. CeO 2 -based catalysts with special morphologies have aroused widespread attention because of their environmental friendliness, surface binding defects, excellent redox ability, and significant oxygen storage capacity. In addition, the morphologies of these catalysts also modulate the valence state of the element, defect sites, and acid-base properties. Therefore, they have been extensively utilized to reduce air pollutants. In this review, the preparation and application of CeO 2 -based catalysts with special morphologies, such as hollow, cubic, rod-like, and others, have been summarized, followed by an in-depth examination of the advantages and mechanisms of these catalysts toward eliminating air pollutants. Finally, the challenges associated with the preparation and application of CeO 2 -based catalysts with special morphologies are presented. We hope to provide some reference for the future design and synthesis of novel CeO 2 -based catalysts used for the abatement of gas pollutants. [Display omitted] • The preparation and application of CeO 2 -based catalysts with special morphologies are introduced. • The application of CeO 2 -based catalysts with special morphologies for air pollutants abatement are presented. • Reaction mechanisms of air pollutants abatement based on CeO2-based catalysts with special morphologies are discussed. [ABSTRACT FROM AUTHOR]

Photocatalytic reduction of CO 2 into hydrocarbon fuels, utilizing inexhaustible solar energy to simulate natural photosynthesis, is a promising approach to simultaneously alleviate environmental issues and energy crises. Among the developed photocatalysts, bismuth (Bi)-based materials have been extensively applied for photocatalytic CO 2 reduction due to their unique electronic configuration and excellent physicochemical properties. Various approaches have been investigated to enhance the photocatalytic performance of Bi-based photocatalysts for CO 2 reduction, among which constructing direct or indirect Z-scheme by coupling Bi-based materials with matching semiconductors is an effective method. In this review, the latest major advancements in the design of high-efficient Bi-based Z-scheme photocatalysts for photocatalytic CO 2 reduction are summarized, including structural engineering strategies for direct Z-scheme and several patterns of indirect Z-scheme construction. Moreover, the proposed S-scheme structure based on the Z-scheme structure is also briefly discussed. Finally, the current challenges and prospects of the future development of the Bi-based Z-scheme structure for CO 2 photoreduction are also presented and discussed. [Display omitted] • The progress on photocatalytic CO 2 reduction over Bi-based Z-scheme photocatalysts are summarized. • The relationship between Bi-based Z-scheme structure and the photocatalytic CO2 reduction activity was investigated. • The future development of the Bi-based Z-scheme structure for CO 2 photoreduction is discussed. [ABSTRACT FROM AUTHOR]