In this research, we successfully synthesized a series of copper-substituted LaMnO3 catalysts utilizing a straightforward sol-gel method. Among these, the La-Mn-Cu-0.6 sample demonstrated exceptional performance in low-temperature CO catalytic oxidation, achieving a T90 of 209 degrees C. Characterization techniques such as EDX, BET and XPS revealed that the enhanced adsorption and activation of CO on the La-Mn-Cu-0.6 catalyst can be attributed to its extensive wide specific surface area, the presence of a significant quantity of highly oxidizing Mn4+ ions with Olattice, Cu+ ions exhibiting strong adsorption properties and considerable Cu+-Ovacancy-Mn3+ sites. H2-TPR analysis indicated that hydrogen consumption followed a trend consistent with the ratios of Ov and the 'Mn4+/ Mn3+'and 'Cu+/ Cu2+' species, highlighting the superior catalyst reduction capability of the La-Mn-Cu-0.6 catalyst. In-situ DRIFTS spectra techniques facilitated a comprehensive examination of the changes in intermediates changes and the reaction pathways involved in the thermal catalytic oxidation of CO. This study elucidates an optimized mechanism for the Cu-doped LaMn1-yCuyO3-delta; perovskite catalysts, which is primarily governed by the dominant Eley-Rideal (E-R) reaction, supplemented by the Mars-Van Krevelen (Mv-k) pathway as a significant contributor.

In this work, the synthesis of FAU and MFI type Ti-containing zeolites from Ti-bearing blast furnace slag was first achieved via a facile hydrothermal method. The synthesized zeolites were identified to be TiNaX and Ti-NaZSM-5 zeolites, with excellent specific surface area of 663.2 and 325.2 m2/g, respectively. Ti species in the Ti-NaX zeolite contained the framework Ti species and amorphous extraframework Ti species, while the Ti species in Ti-NaZSM-5 zeolite were in the form of the two species of above and another anatase TiO2. To investigate the potential application of the synthesized zeolites in photocatalysis field, an exploratory study was carried out by degradation of methyl orange under UV irradiation. As demonstrated, the Ti-NaZSM-5 zeolite showed higher photocatalytic performance and was more suitable to be the support of the TiO2 photocatalyst than the Ti-NaX zeolite. Innovative conversion of TBFS into Ticontaining zeolite materials does provide not only a novel and low-cost approach to waste management, but also a promising material candidate for catalytic oxidation and environmental purification. (c) 2022 The Society of Powder Technology Japan. Published by Elsevier BV and The Society of Powder Technology Japan. All rights reserved.

Aluminosilicate zeolites have been found to be effective supports of semiconductor photocatalysts for the removal of organic compounds in wastewater and air. In this review, we summarize the progress in the application of zeolite materials such as Y, ZSM-5, mordenite, beta and clinoptilolite for improving the performance of semiconductor photocatalysts in degradation of environmental pollutants. The main synthesis strategies and the mechanisms of organic compounds adsorption and photocatalysis by zeolite-based photocatalysts are explicated in detail. Meanwhile, various types of zeolite-based photocatalytic composites are also thoroughly summarized. The more reliable zeolite-based photocatalysts with high photocatalytic activity under visible or sunlight irradiation should be extensively investigated. Additionally, we highlight the advancements for improving performance of different zeolite-based composites in photocatalytic degradation organic contaminants in wastewater and air. The achieved progress demonstrates that the photocatalytic enhancement of zeolite-based composites is predominantly dependent on the enhanced adsorption performance, as well as the high separation and transfer efficiency of photogenerated charge carriers. Hence, the characteristics of the zeolite-based composites (surface area, pHpzc value, hydrophobic, band gap and band edge), the nature of organic contaminants and other experiment factors need to be taken into account in applying to photodegradation process involving this catalyst. Finally, the current challenges and perspectives for the future research of these photocatalysts are presented.

Waste bamboo-derived activated carbon (BAC), biomass char (BBC), and nitric acid-modified BACN and BBCN supports as well as commercial activated carbon (AC) and corresponding ACN were prepared for comparative study. Their denitrification performance in 100–250 °C decreased as BACN > ACN > BBCN > BAC > AC > BBC. BACN and ACN were separately loaded with different MOx (M = Mn, Ce, Fe, Cu, V) by wet impregnation. M/BACN showed slightly higher NO conversion than corresponding M/ACN. Mn/BACN exhibited the best denitrification performance with NO conversion of 92% at 200 °C. The physicochemical properties of supports and catalysts were characterized by BET, SEM-EDS, FTIR, XRD, and XPS. The results suggested that BAC was most sensitive to HNO3 modification, thereby BACN possessed much more surface functional groups. This was the main reason for BACN exhibiting the best denitrification performance among the supports. Loading metal oxides introduced more strong active sites sharply increasing the catalytic activity, even though decreased the surface area and decomposed a few surface functional groups. Mn/BACN mainly followed the L–H mechanism at low temperature. Rich surface functional groups on BACN could promote the adsorption and activation of NH3 and NO accelerating the reaction in L–H mechanism.

Different crystal phases of MnO2 were synthesized and tested for NH3–SCR of NO and NH3 oxidation performances during 50–120 °C. Among those catalysts, α-MnO2 showed the most superior SCR performance for NOx conversion and N2 selectivity, and NH3 species on its surface were active to react with the oxygen, while NH2 species were also easily oxidized by the oxygen. For β-MnO2, NH3 (ads, B) species and part of NH3 (ads, L) species on its surface were active to react with oxygen, while NH3 (ads, L) species adsorbed at Lewis sites showed low reactive with O2, thereby producing less N2O and low NO conversion. γ-MnO2 showed the similar NOx conversion rates and N2O amount generated from the NH3 oxidation comparing to α-MnO2, while yielding much more N2O generation ratios from SCR reactions conditions. Besides, NH3 (ads, L), NH3 (ads, B), NO32− and NH2 species adsorbed on γ-MnO2 surface had high reactivity and could all be consumed by oxygen rapidly. And the N2O formation of δ-MnO2 mainly generated from SCR reactions conditions in the temperature range of 50–120 °C, while the adsorbed NH3 (ads, L) species were hard to react with O2.

In this work, based on a type of energy band engineering strategy as calcination, TiO2/ZSM-5 hybrids for photodegradation of methyl orange (MO) in water under UV light have been developed via a facile solid state diffusion method. Effects of varied calcination temperatures on TiO2/ZSM-5 hybrids have been systematically characterized including XRD, FT-IR, SEM, TEM, EDX mapping, BET, PL, EIS, UV-vis DRS, active species trapping experiments and Mott-Schottky curves. It was found that the calcination temperature influenced photocatalytic activity, typically on physicochemical properties of materials and adjustment for the energy gap and band position of TiO2. The XRD analysis revealed that hybridization of ZSM-5 kept the crystal phase of TiO2 as anatase unchanged with the high-rising calcined temperature. The optimum sample calcined at 450 degrees C named as Z-T (450) presented nearly 99% degradation rate for MO, owing to optimal uniform distribution, highest specific surface area and best charge separation/transfer efficiency. The FT-IR comparison result that the functional groups and peak strength of the used catalyst were alike as before, showed the stability of photocatalyst. Adoption of calcination strategy does provide not only a clean, low-cost and highly efficient path to approach the complete degradation of azo dyes, but also a chance for photocatalytic technology to fulfill the implementation in industrial applications.

CO2 mineral sequestration is one of the most promising strategies for combating global warming. However, its industrial applications of CO2 mineral carbonation are limited due to the concerns of energy and cost consumption. Simultaneously, recovery of valuable byproducts is essential for favorable economic viability during the mineralization process. In this study, a novel process combining CO2 mineral sequestration and zeolite synthesis by using blast furnace slag was proposed. Si/Al-gel was first prepared by leaching and precipitation of the slag, followed by hydrothermal reaction to synthesize faujasite type zeolite. The process optimization and CO2 net-emission reduction evaluation of the proposed route were conducted in this study. A sole phase faujasite zeolite with high specific surface area (721 m(2)/g) was successfully synthesized under the optimal hydrothermal conditions. The Si/ Al-depleted precipitated mother liquid (rich in MgSO4) together with the CaSO4 center dot 0.5H(2)O leaching residue was used to mineral sequestrate CO2. The total amount of CO2 sequestrated by processing one ton slag was 398 kg. Preliminary evaluation of CO2 netemission reduction indicated that 52 kg of CO2 can be permanently stored for 1000 kg of slag processing after deducting the CO2 released in this process. The major component of blast furnace slag was fully utilized in this process, realizing the double benefits of CO2 emission reduction and solid waste disposal as well as exhibiting great potential for industrial application.

Washing method by sulfuric acid was investigated in the context of deactivation and regeneration mechanism of arsenic deactivated catalyst over V2O5-WO3/TiO2 catalyst. The physical and chemical properties changes for catalysts were characterized by XRD, SEM, BET, Raman, XPS, NH3-TPD and in situ DRIFT, therein including morphology, structure, chemical states, surface acidity and functional groups. The results indicated that arsenic species mainly consisted of As2O5 on the arsenic poisoned catalyst surface. It increased N2O formation due to high active oxygen ratio of poisoned catalyst. After regeneration, the N2O formation was reduced. Arsenic oxides covering on catalyst surface could be almost wipe off with sulfuric acid. As-OH group disappeared, and the Bronsted and Lewis acid sites were re-exposed. Moreover, a new Bronsted acid sites (S-OH) was formed by chelating bidentate sulfates (SO42-) since it introduced S=O into anatase TiO2 lattice. However, some vanadium species were lost and the remaining species tended to form V4+, the activity had an apparent decrease in the temperature range of 300-400 degrees C. (C) 2019 Energy Institute. Published by Elsevier Ltd. All rights reserved.

Different valence states manganese oxides catalysts (MnO2, Mn2O3 and Mn3O4) were synthesized to investigate their N2O formation pathways during NH3–SCR of NO process. In contrast, the NO conversions of Mn2O3 and Mn3O4 were nearly identical, while MnO2 exhibited better NO conversion activity over the whole temperature range and corresponding to NO conversion of 100% at 150 °C with a space velocity of 36,000 h−1. At low temperature, the majority of N2O was generated from the SCR reactions on the three catalysts. With the increasing temperature, the N2O amounts and the N2O generation ratios from NH3 oxidation of the three catalysts both increased. Besides, NH3 species on MnO2 were easier to be oxidized by gaseous O2, while NH3,ads at Lewis acid sites would partly transfer to NH4+ and NH2 species on Mn2O3 in the presence of O2 and more NH2 species would be formed on the oxygen adsorbed surface of Mn3O4. Both E−R and L−H mechanisms were found conducting on the three catalysts. NH2/NH species on the MnO2 surface would react with gaseous NO to form NH2NO/NHNO and then decomposed to N2/N2O, respectively, while the adsorbed monodentate nitrites combined with NH3,ads and/or NH4+ species to form NH4NO2 that decomposed to N2. Besides the formation and decomposition of NH2NO/NHNO, NH4NO3 was also formed on Mn2O3 and Mn3O4, and then decomposing to N2O.

A series of CeO2 photocatalysts were synthesized through the molten salt method. The photocatalytic activity was evaluated through the degradation of methyl orange (MO). Systematic characterizations including X-ray diffraction, Scanning electron microscopy, Fourier transformed infrared, X-ray photoelectron spectroscopy, Raman spectroscopy, electron spin-resonance spectroscopy, UV-vis diffuse reflectance spectroscopy, photoluminescence spectrometry, photocurrent response and electrochemical impedance spectroscopy were conducted to study the as-prepared CeO2 samples. It was found that, under ultraviolet light irradiation, the apparent rate constants of CeO2 prepared at 800 degrees C for degradation of MO was about 3.4 times higher than CeO2 prepared at 500 degrees C. CeO2 prepared at 800 degrees C held the higher oxygen vacancies concentration. According to the trapping experiments, it was demonstrated that photo-generated holes played a dominant role in this photocatalytic system. Furthermore, the possible photocatalytic mechanism which showed the roles of photo-generated holes and oxygen vacancies was proposed. (C) 2020 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

MnOx-CeO2 (denoted as Mn–Ce) nanorod and MnOx-CeO2 nanooctahedra catalysts were synthesized by the hydrothermal method and were used for selective catalytic reduction of NO with NH3. The catalytic performance tests showed that the NO removal efficiency of CeO2 catalysts was obviously improved after loading MnOx. The structure and properties of catalysts had been characterized by SEM、TEM、XRD、BET、XPS、H2-TPR、NH3-TPD and in situ DRIFTS. It was found that Mn–Ce catalyst were of uniform core-shell structure, higher concentrations of Mn4+ and Ce3+, better reducibility, the increase of weak acid sites. The results of in situ DRIFTS indicated that the NH3-SCR reaction should obey the E–R mechanism. Moreover, the promotion effect and mechanism of MnOx doped CeO2 was demonstrated, which improved the catalytic activity of Mn–Ce catalysts.

Enhanced performance of Ce doping on the catalytic activity of V2O5-WO3/TiO2 catalysts and its resistance properties to Na poisoning have been investigated in the research. Different Na species (NaCl and Na2O) were deposited on CeO2-V2O(5)-WO3/TiO2 catalysts by impregnation method. The results presented that CeO2-V2O5WO3/Tio(2) catalysts exhibited a higher NH3-SCR activity and better Na resistance than the V2O5-WO3/TiO2 catalyst, and its poisoning resistance to Na2O is more superior than to NaCl, caused by more acid sites over the 10%CeO2-V2O5-WO3/TiO2 (Ce10VWTi) catalyst, which indicated that the poisoning resistance of Na2O on Ce10VWTi catalysts is higher than that of NaCl. Combined with the characterization results, the dopant of Ce could enhance the surface chemisorbed oxygen on the Na poisoning V2O5-WO3/TiO2 catalysts, facilitate the redox cycle, and increase the intensity of acid sites due to the newly formed Bronsted acid sites stemmed from Ce3+ - NH4+, thereby promoting catalytic activity and Na poisoning resistance.

Photocatalytic technology has bright prospects in the field of coking wastewater treatment. UV spectrophotometer is used to test the photodegradation of 10 mol/L rhodamine B solution on the self-built photocatalytic platform. The photocatalytic properties of 7 kinds of catalysts are compared and analyzed. The results show that after the 30min simulation of sunlight, the photocatalytic effect from the best to the worst is 10%CeO2-TiO2/10% RGO >5% CeO2-TiO2/10% RGO >1% CeO2-TiO2/10% RGO >TiO2/10% RGO >10% CeO2-TiO2. In the case of the TiO2 composite with single modified materials of the same mass, the composite with graphene has better photocatalytic properties than the composite with CeO2 while the TiO2 composite with two modified materials shows better photocatalytic effect than that with only one single material, and the samples with more CeO2 have more excellent photocatalytic properties in the case of the same mass of graphene. And the photocatalytic performance of 10%CeO2-TiO2/10%RGO composites is the best, whose photocatalytic degradation is 6.71 times that of pure TiO2. The results show that the composite of graphene and CeO2 effectively improves the photocatalytic efficiency and improves the defects of TiO2 to a certain extent.

V2O5-WO3/TiO2 catalyst has been widely used in industry. Alkali metals would cause the deactivation of V2O5-WO3/TiO2 catalyst. In this paper, the poisoning deactivation of NaCl and Na2O on V2O5-WO3/TiO2 catalyst was compared. The properties of the catalysts were characterized by BET, XPS, H2-TPR, NH3-TPD and in situ DRIFTS. It was found the addition of NaCl, Na2O affected the structure, redox properties and acid sites of V2O5-WO3/TiO2 catalyst. Na+ would react with VOH to form VONa+ destroying the structure of Brønsted sites and affect the adsorption of NH3 on the Lewis acid to restrain the generation of V4+NH2 to decrease the SCR activity, occupying the oxygen vacancy made a decline in chemisorbed oxygen. The poisoning effect of NaCl was stronger than that of Na2O, even if the property of weak-chemisorption of NaCl is stronger and possessed more V5+ species. There is a reason that NaCl provided HCl and then reacted with VO2 to form ClVOClOH to adsorb NH3. However, ClVOClOH cannot make the catalysis selectively generate nitrogen and water.

The TiO2-graphene (TiO2-GR) composites have been successfully synthesized through the hydrothermal reaction. Different structures of TiO2-GR composites were modified using graphene oxide (GO) and different titanium sources in hydrothermal conditions. The structure and properties of the photocatalysts have been characterized by field emission scanning electron microscope (FESEM), x-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), x-ray photoelectron spectroscopy (XPS), photoluminescence spectra (PL), UV–vis diffuse reflectance spectra (DRS), and Brunauer–Emmett–Teller (BET). The results showed that due to the larger interfacial contact between TiO2 and graphene, and its greater surface area, the poriferous TiO2-GR composite exhibited the best photocatalytic properties and adsorption performance compared with the other nanocomposites.