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NiFe layered double hydroxides (NiFe-LDH) exhibited an outstanding performance and promising application potential for removing ozone. However, the effect of interlayer anions on ozone removal remains ambiguous. Here, a series of NiFe-LDH with different interlayer anions (F - , Cl - , Br - , NO 3 - , CO 3 ) were prepared to investigate the effect of the interlayer anion on ozone removal for the first time. It was found that the interlayer anions are a key factor affecting the water resistance of the NiFe-LDH catalyst under moist conditions. NiFe-LDH-CO 2- , and SO 4 will undergo coordination changes through the interaction with water molecules under moist conditions, exposing new metal sites. As a result, the newly exposed metal sites could activate water molecules into hydroxyl groups that act as active sites for catalyzing ozone decomposition. This work provides a new insight into the interlayer anions of LDH, which is important for the design and development of LDH catalysts with excellent ozone removal properties.2- ) were prepared to investigate the effect of the interlayer anion on ozone removal for the first time. It was found that the interlayer anions are a key factor affecting the water resistance of the NiFe-LDH catalyst under moist conditions. NiFe-LDH-CO 3 2- exhibited the best water resistance, which was much better than that of NiFe-LDH containing other interlayer anions. The in situ DIRFTS demonstrates that the carbonates in the interlayer of NiFe-LDH-CO 3 2- will undergo coordination changes through the interaction with water molecules under moist conditions, exposing new metal sites. As a result, the newly exposed metal sites could activate water molecules into hydroxyl groups that act as active sites for catalyzing ozone decomposition. This work provides a new insight into the interlayer anions of LDH, which is important for the design and development of LDH catalysts with excellent ozone removal properties.

Ground-level ozone is harmful to human beings and ecosystems, while room-temperature catalytic decomposition is the most effective technology for ozone abatement. However, solving the deactivation of existing metal oxide catalysts was caused by oxygen-containing intermediates is challenging. Here, we successfully prepared a two-dimensional NiFe layered double hydroxide (NiFe-LDH) catalyst via a facile co-precipitation method, which exhibited stable and highly efficient performance of ozone decomposition under harsh operating conditions (high space velocity and humidity). The NiFe-LDH catalyst with Ni/Fe = 3 and crystallization time over 5 hr (named Ni 3 Fe-5) exhibited the best catalytic performance, which was well beyond that of most existing manganese-based oxide catalysts. Specifically, under relative humidity of 65% and space velocity of 840 L/(g·hr), Ni 3 Fe-5 showed ozone conversion of 89% and 76% for 40 ppmV of O 3 within 6 and 168 hr at room-temperature, respectively. We demonstrated that the layered structure of NiFe-LDH played a decisive role in its outstanding catalytic performance in terms of both activity and water resistance. The LDH catalysts fundamentally avoids the deactivation caused by the occupancy of oxygen vacancies by oxygen-containing species (H 2 O, O - , and O 2- ) in manganese-based oxide. This study indicated the promising application potential of LDHs than manganese-based oxide catalysts in removal of gaseous ozone., (Copyright © 2021. Published by Elsevier B.V.)

Clarifying the driving forces of O 3 and fine particulate matter (PM 2.5 ) co-pollution is important to perform their synergistic control. This work investigated the co-pollution of O 3 and PM 2.5 in Hainan Province using an observation-based model and explainable machine learning. The O 3 and PM 2.5 pollution that occurs in winter is affected by the wintertime East Asian Monsoon. The O 3 formation shifts from a NO x -limited regime with a low O 3 production rate (P O3 ) in the non-pollution season to a transition regime with a high P O3 in the pollution season due to an increase in NO x concentrations. Increased O 3 and atmospheric oxidation capacity promote the conversion from gas-phase precursors to aerosols. Meanwhile, the high concentration of particulate nitrate favors HONO formation via photolysis, in turn facilitating O 3 production. Machine learning reveals that NO x promotes O 3 and PM 2.5 co-pollution during the pollution period. The P O3 shows an upward trend at the observation site from 2018 to 2022 due to the inappropriate reduction of volatile organic compounds (VOCs) and NO x in the upwind areas. Our results suggest that a deep reduction of NO x should benefit both O 3 and PM 2.5 pollution control in Hainan and bring new insights into improving air quality in other regions of China in the future., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Ozone (O 3 ) removal has important implications for environmental protection and human health, and Ag-Mn catalysts have shown promising O 3 decomposition. Catalysts with Ag supported on porous cube-like α-Mn 2 O 3 (Ag/Mn-C) with high utilization of Ag were prepared by the impregnation method and showed excellent O 3 decomposition activity. Physicochemical characterizations demonstrated that metallic Ag nanoparticles (Ag n 0 ) were mainly anchored on manganese vacancies, forming Ag-O-Mn bonds between Ag n 0 and α-Mn 2 O 3 -C. The abundant manganese vacancies of α-Mn 2 O 3 -C can lead to Ag n 0 with a smaller particle size and more uniform dispersion, thereby resulting in markedly enhanced O 3 decomposition performance compared to Ag n 0 with a large particle size and uneven distribution on rod-like α-Mn 2 O 3 (Ag/Mn-R). Under a relative humidity of 65% and a space velocity of 1,110,000 h -1 , the conversion of 40 ppm O 3 over the 2%Ag/Mn-C catalyst within 6 h (98%) at 30 °C was more than twice as high as that of the 2%Ag/Mn-R catalyst (42%). The study provides guidance for the design of highly efficient Ag-based catalysts and the understanding of the microstructure of supported catalysts.

Ag-Mn catalysts with excellent water resistance and ozone decomposition activity were successfully synthesized by simple precipitation and impregnation methods. Under a relative humidity of 65% and space velocity of 840,000 h -1 , the 6%Ag/α-Mn 2 O 3 -I catalyst showed 99% conversion of 40 ppm O 3 after 6 h, which was far superior to the performance of the 6%AgMnO x -C (49%), 6%Ag/MnCO 3 -I (32%), and α-Mn 2 O 3 (5%) catalysts. Physicochemical characterization indicated that the chemical state of Ag on the Ag-Mn catalysts determined the O 3 decomposition activity of the catalysts. The Ag species on the 6%Ag/α-Mn 2 O 3 -I catalyst were mainly metallic silver nanoparticles (Ag n ), which exhibited much better ozone decomposition performance than the Ag 0 ), which exhibited much better ozone decomposition performance than the Ag 1.8 Mn 8 O 16 and oxidized silver clusters (Ag n δ+ ) existing on the 6%Ag/MnCO 3 -I and 6%AgMnO x -I catalyst still had above 85% ozone conversion after 60 h under a relative humidity of 65% and space velocity of 840,000 h 2 O 3 -I catalyst still had above 85% ozone conversion after 60 h under a relative humidity of 65% and space velocity of 840,000 h -1 atmosphere, which indicated that it is a promising catalyst for ozone decomposition. This research provides guidance for the subsequent development of Ag-Mn catalysts for ozone decomposition with high activity.n 0 , and its activity could be completely recovered by treatment at 350 °C under an N 2 atmosphere, which indicated that it is a promising catalyst for ozone decomposition. This research provides guidance for the subsequent development of Ag-Mn catalysts for ozone decomposition with high activity.

Ozone (O 3 ), as a harmful air pollutant, has been of wide concern. Safe, efficient, and economical O 3 removal methods urgently need to be developed. Catalytic decomposition is the most promising method for O 3 removal, especially at room temperature or even subzero temperatures. Great efforts have been made to develop high-efficiency catalysts for O 3 decomposition that can operate at low temperatures, high space velocity and high humidity. First, this review describes the general reaction mechanism of O 3 decomposition on noble metal and transition metal oxide catalysts. Then, progress on the O 3 decomposition performance of various catalysts in the past 30 years is summarized in detail. The main focus is the O 3 decomposition performance of manganese oxides, which are divided into supported manganese oxides and non-supported manganese oxides. Methods to improve the activity, stability, and humidity resistance of manganese oxide catalysts for O 3 decomposition are also summarized. The deactivation mechanisms of manganese oxides under dry and humid conditions are discussed. The O 3 decomposition performance of monolithic catalysts is also summarized from the perspective of industrial applications. Finally, the future development directions and prospects of O 3 catalytic decomposition technology are put forward., Competing Interests: Declaration of Competing Interest None., (Copyright © 2020. Published by Elsevier B.V.)

In the study, the catalyst precursors of Ce-modified γ-MnO 2 were washed with deionized water until the pH value of the supernatant was 1, 2, 4 and 7, and the obtained catalysts were named accordingly. Under space velocity of 300,000 hr -1 , the ozone conversion over the pH = 7 catalyst under dry conditions and relative humidity of 65% over a period of 6 hr was 100% and 96%, respectively. However, the ozone decomposition activity of the pH = 2 and 4 catalysts distinctly decreased under relative humidity of 65% compared to that under dry conditions. Detailed physical and chemical characterization demonstrated that the residual sulfate ions on the pH = 2 and 4 catalysts decreased their hydrophobicity and then restrained humid ozone decomposition activity. The pH = 2 and 4 catalysts had inferior resistance to high space velocity under dry conditions, because the residual sulfate ion on their surface reduced their adsorption capacity for ozone molecules and increased their apparent activation energies, which was proved by temperature programmed desorption of O 2 and kinetic experiments. Long-term activity testing, X-ray photoelectron spectroscopy and density functional theory calculations revealed that there were two kinds of oxygen vacancies on the manganese dioxide catalysts, one of which more easily adsorbed oxygen species and then became deactivated. This study revealed the detrimental effect of surface acid ions on the activity of catalysts under humid and dry atmospheres, and provided guidance for the development of highly efficient catalysts for ozone decomposition., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier B.V.)

To clarify how coexisting atmospheric pollutants affect secondary organic aerosol (SOA) formation, we investigated the effects of mixed gaseous pollutants (CO and SO 2 ) and mixed organic-inorganic (MOI) particles on SOA formation during n -butyl vinyl ether (BVE) ozonolysis. Higher CO levels (90 ppm) were found to significantly change the chemical composition of SOA (prompting monomers while reducing oligomer formation) without causing much change in the overall SOA mass. Based on the positive matrix factorization (PMF) analysis, heterogeneous chemical conversions between preformed and newly formed SOA were the major pathways of SOA formation in the presence of MOI particles. Furthermore, MOI particles had an enhancing effect on SOA formation at 1% relative humidity (RH) but a negligible effect at higher RH (10 and 55%). The enhancing effect was attributed to the formation of multifunctional products resulting from high functionalization of preformed and newly formed SOA. The negligible effect observed was ascribed to the cleavage of unstable oligomers as a result of the reversible oligomerization of preformed and newly formed SOA. Even so, MOI particles could still affect the composition of newly formed SOA. These results highlight the need to account for the significant effect of mixed gaseous and particulate pollutants on both SOA constituents and their evolution.

The performance of Ce-OMS-2 catalysts was improved by tuning the fill percentage in the hydrothermal synthesis process to increase the oxygen vacancy density. The Ce-OMS-2 samples were prepared with different fill percentages by means of a hydrothermal approach (i.e. 80%, 70%, 50% and 30%). Ce-OMS-2 with 80% fill percentage (Ce-OMS-2-80%) showed ozone conversion of 97%, and a lifetime experiment carried out for more than 20 days showed that the activity of the catalyst still remained satisfactorily high (91%). For Ce-OMS-2-80%, Mn ions in the framework as well as K ions in the tunnel sites were replaced by Ce 4+ , while for the others only Mn ions were replaced. O 2 -TPD and H 2 -TPR measurements proved that the Ce-OMS-2-80% catalyst possessed the greatest number of mobile surface oxygen species. XPS and XAFS showed that increasing the fill percentage can reduce the AOS of Mn and augment the amount of oxygen vacancies. The active sites, which accelerate the elimination of O 3 , can be enriched by increasing the oxygen vacancies. These findings indicate that increasing ozone removal can be achieved by tuning the fill percentage in the hydrothermal synthesis process., (Copyright © 2019. Published by Elsevier B.V.)

Manganese oxides are prominent candidates for the catalytic oxidation of volatile organic compounds (VOCs) or ambient decomposition of O 3 individually. Here, we compared various preparation methods to create a defect-enriched Ag-MnO x nanocomposite that exhibits a remarkably multifunctional activity in VOC combustion and ozone decomposition. Ag + ions were well-dispersed in the microtunnels of Ag-MnO x -H via hydrothermal replacement of the original K + ions; this catalyst's benzene combustion efficiency ( T 90% = 216 °C at a space velocity of 90 000 mL h -1 ) was comparable to that of typical noble metal catalysts. Moreover, the decomposition of ozone over the Ag-MnO -1 ) was comparable to that of typical noble metal catalysts. Moreover, the decomposition of ozone over the Ag-MnO x -H catalyst (space velocity = 840 000 mL h -1 ) under a relative humidity of 60% was above 90%, indicating that it is a promising material for ozone elimination in practical application. The local structure results indicated that silver incorporation via the hydrothermal method facilitates the formation of nonstoichiometric defects in the MnO -1 ) under a relative humidity of 60% was above 90%, indicating that it is a promising material for ozone elimination in practical application. The local structure results indicated that silver incorporation via the hydrothermal method facilitates the formation of nonstoichiometric defects in the MnO x matrix. The large number of active oxygen species related to O vacancies appeared to play critical roles in VOC combustion; moreover, the oxygen vacancies originating from O defects were also critical in O 3 abatement. This work provides multifunctional catalysts for VOC combustion and ambient O 3 decomposition and may assist with the rational design of MnO x catalysts for application in various conditions.

Alkyl vinyl ethers are widely used as fuel additives. Despite this, their atmospheric chemistry and secondary organic aerosol (SOA) formation potentials are still not well-known under complex pollution conditions. In this work, we examined the impact of SO 2 , relative humidity (RH), and particle acidity on the formation and oxidation state (OSc) of SOA from butyl vinyl ether (BVE) ozonolysis. Increasing SO 2 concentration produced a notable promotion of SOA formation and OSc due to the significant increase in H 2 SO 4 particles and formation of more highly oxidized components. Increased RH in the presence of SO 2 appeared to promote, suppress, and dominate the formation and OSc of SOA in the dry range (1-10%), low RH range (10-42%), and moderate RH range (42-64%), respectively. This highlights the importance of competition between H 2 O and SO 2 in reacting with the stabilized Criegee intermediate in BVE ozonolysis at ambient RH. Increased particle acidity mainly contributed to the change in chemical composition of BVE-dominated SOA but not to SOA formation. The results presented here extend previous analysis of BVE-derived SOA and further aid our understanding of SOA formation potential of BVE ozonolysis under highly complex pollution conditions.

O 3 decomposition catalysts with excellent performance still need to be developed. In this study, Ag-modified manganese oxides (AgMnO x ) were synthesized by a simple co-precipitation method. The effect of calcination temperature on the activity of MnO x and AgMnO x catalysts was investigated. The effect of the amount of Ag addition on the activity and structure of the catalysts was further studied by activity testing and characterization by a variety of techniques. The activity of 8%AgMnO x for ozone decomposition was significantly enhanced due to the formation of the Ag 1.8 Mn 8 O 16 structure, indicating that this phase has excellent performance for ozone decomposition. The weight content of Ag 1.8 Mn 8 O 16 in the 8%AgMnO x catalyst was only about 33.76%, which further indicates the excellent performance of the Ag 1.8 Mn 8 O 16 phase for ozone decomposition. The H 2 temperature programmed reduction (H 2 -TPR) results indicated that the reducibility of the catalysts increased due to the formation of the Ag 1.8 Mn 8 O 16 structure. This study provides guidance for a follow-up study on Ag-modified manganese oxide catalysts for ozone decomposition., (Copyright © 2018. Published by Elsevier B.V.)

Transition metal (cerium and cobalt) doped γ-MnO 2 (M-γ-MnO 2 , where M represents Ce, Co) catalysts were successfully synthesized and characterized. Cerium-doped γ-MnO 2 materials showed ozone (O 3 ) conversion of 96% for 40 ppm of O 3 under relative humidity (RH) of 65% and space velocity of 840 L g -1 h -1 after 6 h at room temperature, which is far superior to the performance of the Co-γ-MnO 2 (55%) and γ-MnO 2 (38%) catalysts. Under space velocity of 840 L g -1 h -1 , the conversion of ozone over the Ce-γ-MnO 2 catalyst under RH = 65% and dry conditions within 96 h was 60% and 100%, respectively, indicating that it is a promising material for ozone decomposition. XRD and HRTEM data suggested that Ce-γ-MnO 2 formed mixed crystals consisting of α-MnO 2 and γ-MnO 2 with specific surface area increased from 74 m 2 /g to 120 m 2 /g compared to undoped γ-MnO 2 , thus more surface defects were introduced. H 2 -TPR, O 2 -TPD, XPS, Raman, and EXAFS confirmed that Ce-γ-MnO 2 exhibited more surface oxygen vacancies and surface defects, which play a key role during the decomposition of ozone. This study provides important insights for developing improved catalysts for gaseous ozone decomposition and promoting the performance of manganese oxide for practical ozone elimination.

Large uncertainty among the measured uptake coefficients of O(3) on soot highlights the importance of the sources and chemical structures of soot samples in this reaction. Soot samples with different microstructures were prepared by combusting n-hexane under controlled conditions. Their reactivities to O(3) were further investigated using in situ Raman spectroscopy. The fuel/oxygen ratio in the combustion experiments not only affected the diameter of the primary particles, but also influenced the micro-chemical structure of soot. Average diameters of soot particles decreased with the decreasing fuel/oxygen ratio. Compared to the "fuel-rich" flame soot, the "fuel-lean" flame soot showed lower structural uniformity with higher disordered carbon content at the graphene layer edges (D1 band) and the surface graphene layers (D2 band) and the amorphous carbon content (D3 band). This disordered carbon was identified as the reactive component for the ozonization of both the "fuel-rich" and "fuel-lean" flame soot samples. The kinetics study demonstrated that the disordered carbon at the surface graphene layers was more active than that at the graphene layer edges in one sample, and the reactivity of these two microstructures types to O(3) in the "fuel-rich" flame soot was higher than that in the "fuel-lean" flame soot.

Soot aerosols are ubiquitous in the atmosphere and play an important role in global and regional radiative balance and climate. Their environmental impact, however, greatly depends on their structure, composition, particle size, and morphology. In this study, the structural changes of a model soot (Printex U) during a heterogeneous reaction with 80 ppm O(3) at 298 K were investigated using in situ Raman spectroscopy, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and transmission electron microscopy (TEM). Hygroscopic changes due to heterogeneous reaction with O(3) were also studied by water sorption analyzer. The consumption of amorphous carbon (D3 band) and disordered graphitic lattice (D4 band) of soot by ozonization was confirmed by the decrease in the full widths at half maximum and their relative integrated intensities (percentages of integrated areas). Oxygen containing surface species including ketone, lactone, and anhydride were also observed in Raman and IR spectra of ozonized soot. The ozonized soot showed more compacted aggregates with a smaller average diameter of primary particles (29.9 +/- 7.7 nm) and a larger fractal dimension (1.81 +/- 0.08) when compared with fresh soot (36.9 +/- 9.4 nm, and 1.61 +/- 0.10). The ozonization reaction leads to an enhancement of hygroscopicity of soot due to the decrease in particle diameter and the formation of oxygen containing surface species.

Smog chamber experimental systems, which have been widely used in laboratory simulation for studying atmospheric processes, are comprehensively reviewed in this paper. The components, development history, main research topics and main achievements of smog chambers are introduced. Typical smog chambers in the world, including their volumes, wall materials, light sources and features, are summarized and compared. Key factors of smog chambers and their influences on the simulation of the atmospheric environment are discussed, including wall loss, wall emission and background pollutants. The features of next-generation smog chambers and their application prospect in future studies of the atmospheric environment are also outlined in this paper. [ABSTRACT FROM AUTHOR]

Ag/MnO x catalysts have great prospects for practical application in ozone decomposition due to their excellent activity and water resistance; yet, improving the stability of Ag/MnO x catalysts for ozone decomposition remains challenging. Here, the addition of alkali metals significantly improved the stability of 2%Ag/MnO 2 catalyst for ozone decomposition under humid conditions. Alkali metals donate electrons to Ag nanoparticles through oxygen bridges, forcing Ag active sites to become hydroxylated by promoting the dissociation of H 2 O molecules, and finally forming new stable hydroxylated Ag active sites (Ag-O(OH) x -K). The O 2 2- species on the new active sites of the 2%K-2%Ag/MnO 2 catalyst can easily desorb; therefore, the hydroxylated active sites can remain stable. These factors are key to the stable ozone decomposition activity of 2%K-2%Ag/MnO 2 catalyst in humid gas. This study represents a critical step towards the design and synthesis of high-stability catalysts for ozone decomposition. [Display omitted] Alkali metals improve the ozone decomposition stability under humid conditions. Alkali metals induce the formation of new stable hydroxylated Ag active sites. The O 2 2- species on the hydroxylated Ag active sites are easier to desorb. [ABSTRACT FROM AUTHOR]

Abstract: The heterogeneous reactions of O3 with anthracene adsorbed on TiO2 and on Asian dust storm particles were investigated in the dark and in the presence of light. The reaction rate constants of the heterogeneous reaction between O3 and anthracene adsorbed on TiO2 were increased by a factor of 1.5 in the presence of light compared to the dark conditions. Anthraquinone, which was identified as the main surface product of anthracene reacted with O3 in the dark, can react with O3 quickly in the presence of light. The reactions on Asian dust storm particles exhibited pseudo-first-order kinetics for anthracene loss, and the reactions between O3 and anthracene adsorbed on Asian dust storm particles proceed by the Langmuir–Hinshelwood mechanism in the dark and in the presence of light. At extremely high ozone concentrations, the degradation of anthracene is enhanced by a factor of 3 in the presence of light compared to the dark conditions. [Copyright &y& Elsevier]

Abstract: To further understand the role of substrates on the heterogeneous reactions of polycyclic aromatic hydrocarbons, the reactions of ozone with anthracene adsorbed on different mineral oxides (SiO2, α-Al2O3 and α-Fe2O3) and on Teflon disc were investigated in dark at 20 °C. No reaction between ozone and anthracene on Teflon disc was observed when the ozone concentration was ∼1.18 × 1014 molecules cm−3. The reactions on mineral oxides exhibited pseudo-first-order kinetics for anthracene loss, and the pseudo-first-order rate constant (k 1,obs) displayed a Langmuir–Hinshelwood dependence on the gas-phase ozone concentration. The adsorption equilibrium constants for ozone (K O3) on SiO2-1, SiO2-2, α-Al2O3 and α-Fe2O3 were (0.81 ± 0.26) × 10−15 cm3, (2.83 ± 1.17) × 10−15 cm3, (2.48 ± 0.77) × 10−15 cm3 and (1.66 ± 0.45) × 10−15 cm3, respectively; and the maximum pseudo-first-order rate constant (k 1,max) on these oxides were (0.385 ± 0.058) s−1, (0.101 ± 0.0138) s−1, (0.0676 ± 0.0086) s−1 and (0.0457 ± 0.004) s−1, respectively. Anthraquinone was identified as the main surface product of anthracene reacted with ozone. Comparison with previous research and the results obtained in this study suggest that the reactivity of anthracene with ozone and the lifetimes of anthracene adsorbed on mineral dust in the atmosphere are determined by the nature of the substrate. [Copyright &y& Elsevier]

[Display omitted] • An innovative Li-K-OMS-2 catalyst for ozone decomposition was designed and prepared. • The catalyst possessed specific H 2 O adsorption sites and thus displayed excellent water resistance for ozone decomposition. • Tuning the Li+-K+ into the OMS-2 tunnels facilitated oxygen vacancy formation. • The water resistance mechanism of Li-K-OMS-2 for ozone catalytic decomposition was proposed. OMS-2-based catalysts hold the promise of practical applications in ozone decomposition for their excellent activity, yet improvement of water resistance property remains challenging. Here, we reported an innovative Li-K-OMS-2 catalyst which possessed specific non-oxygen vacancy sites for H 2 O adsorption in the tunnel framework. This catalyst showed the decrease of only ∼10 % of ozone conversion after reaction for 6 h under the RH of 90 %, the initial ozone concentration of 45 ppm and GHSV of 660,000h−1 at 25 °C, which was superior to the currently documented MnO 2 -based catalysts. Both physiochemical characterization and DFT calculations revealed that the excellent water resistance property of Li-K-OMS-2 could be attributed to the formation of designed novel non-oxygen vacancy sites for H 2 O adsorption, which effectively alleviated the catalyst deactivation caused by non-dissociative adsorption of H 2 O on oxygen vacancies. The findings represented a critical step towards the rational design and synthesis of high water-resistant catalyst for ozone decomposition. [ABSTRACT FROM AUTHOR]

• LDH catalyst with superior reactivity and durability for catalyzing ozone decomposition were synthesized by a facile method. • LDH catalyst exhibits catalytic performance far superior to that of existing MnOx-based catalysts. • LDH catalyst fundamentally solve the deactivation of oxygen vacancy for catalyzing ozone decomposition. • The robust H-transfer redox mechanism determines the high-efficiency catalytic performance of LDH catalyst. • LDH catalyst is a promising material for ozone decomposition. Numerous catalytic reaction systems take oxygen vacancy as the active site to initiate the redox cycle. However, the oxygen vacancy is easily occupied by various oxygen-containing species (e.g., water or other intermediates), resulting in catalyst deactivation. Here, we demonstrate that the layered double hydroxide (LDH) catalysts fundamentally solve the deactivation of oxygen vacancy frequently encountered with metal oxide catalyst systems, which simultaneously realizes the superior reactivity and durability for catalyzing ozone decomposition. First-principles calculations reveal that the ubiquitous surface hydroxyls on the layered hydroxide serve as the reactive sites and the redox cycle is achieved by a robust H-transfer mechanism in the 2D confined LDH systems, which are responsible for the extraordinary activity and resistance of LDH catalysts. [ABSTRACT FROM AUTHOR]

• CeMn a O x for highly efficient catalytic decomposition of ozone were synthesized by a facile method. • The ozone decomposition activity of α-Mn 2 O 3 increased by a factor of 2.5 with the addition of Ce. • Cerium-manganese complex oxides play a key role in the decomposition of ozone. • CeMn a O x is a promising material for ozone decomposition. Novel CeMn a O x (a is the molar ratio of Mn to Ce) catalysts for catalytic decomposition of ozone (O 3) under high GHSV conditions were successfully synthesized by a facile homogeneous precipitation method. CeMn 10 O x showed ozone conversion of 96 % for 40 ppm O 3 under relative humidity (RH) of 65 % and space velocity of 840 L·g−1 ·h-1 after 6 h at room temperature, which is far superior to the performance of the α-Mn 2 O 3 (38 %). The ozone decomposition activity of α-Mn 2 O 3 increased by a factor of 2.5 with the addition of Ce. XRD, XPS, H 2 -TPR, O 2 -TPD, EXAFS and DFT calculations data confirmed that cerium-manganese complex oxides with enhanced surface area were formed, which played a key role in the decomposition of ozone. This study provides important insights for developing improved catalysts for gaseous ozone decomposition that can be prepared by a simple method, and promoting the performance of manganese oxides for practical ozone elimination. [ABSTRACT FROM AUTHOR]

Herein, NiFe layered double hydroxide (NiFe-LDH) monolithic catalysts self-supported by metal foam were synthetized in-situ by a simple one-step hydrothermal method, and were first used for ozone elimination. NiFe-LDH/IF (Iron Foam, IF) monolithic catalysts were successfully prepared in the absence of ammonium fluoride (NH 4 F), avoiding the production of wastewater containing fluorine. The optimized NiFe-LDH/IF monolithic catalyst exhibited ozone conversion of 91.5% and 85% after 6 and 168 h, respectively, under harsh conditions, showing promising potential for ozone pollution control. This study provided a convenient and eco-friendly method for the preparation of monolithic catalyst. [Display omitted] • The monolithic NiFe-LDH catalyst was prepared by a simple and eco-friendly one-step hydrothermal method. • The NiFe-LDH in-situ grows on the metal foam, which is not only the support for catalyst but also a source of metal ions. • The optimized NiFe-LDH/IF monolithic catalyst exhibited excellent activity and stability for eliminating ozone. [ABSTRACT FROM AUTHOR]

Catalytic decomposition is a promising method of ozone (O 3) removal, and Ag-based catalysts have shown excellent O 3 decomposition performance. In this study, the chemical states of Ag species were successfully regulated by varying the loading of Ag and the particle size of α-Fe 2 O 3 supports, and the O 3 decomposition performance of different Ag species (monatomic Ag, Ag clusters (1–2 nm), small Ag nanoparticles (3–5 nm), large Ag nanoparticles (7–12 nm)) was determined. The changes undergone by Ag species after exposure to ozone were characterized in detail, and the ozone decomposition performance of the corresponding Ag species was determined. The terminal and doubly bridging hydroxyl groups on the Fe 2 O 3 support were determined to be the anchoring sites for Ag species. The Ag species and Fe 2 O 3 support are connected through oxygen bridges, forming Ag-O-Fe linkages. This study provides guidance for understanding the mechanism of the interaction between metals and supports and follow-up development of high-efficiency Ag-based catalysts. [Display omitted] • The terminal and doubly bridging hydroxyl groups are the anchoring sites of Ag. • The Ag species are anchored on the Fe 2 O 3 support by Ag-O-Fe linkages. • Small Ag nanoparticles and highly dispersed Ag n δ+ are good active sites for O 3 decomposition. [ABSTRACT FROM AUTHOR]

Surface ozone pollution is a significant environmental problem. In addition to the control of ozone precursors, direct catalytic decomposition of ozone is an effective control method with broad prospects. At present, the evaluation of the ozone decomposition performance of catalysts is typically performed in the laboratory, and the lack of scientific evaluation means to apply them to complex ambient atmosphere limits the practical application of ozone removal catalysts. Here, we devised a new evaluation method for ozone catalytic decomposition materials in the ambient atmosphere that can comprehensively evaluate the influence of various factors in the ambient atmosphere on performance. The results showed that ozone catalytic decomposition materials can maintain a decomposition efficiency of more than 20% in ambient atmosphere. The decomposition efficiency is mainly affected by distance, the closer the distance; the higher the decomposition efficiency. In addition, the concentration of ozone in the environment also affects the decomposition efficiency and shows a positive correlation. As the ozone concentration increased, the decomposition efficiency increased. An increase in relative humidity can cause a decline in decomposition efficiency, but this effect is eliminated with a decrease in humidity. In addition, the ozone catalytic decomposition materials can reduce the ozone concentration in the environment from 160 μg/m3to less than 100 μg/m3, which can play a great role in environmental ozone pollution control. [Display omitted] • We established the test of ozone decomposition materials in ambient atmosphere. • Ozone decomposition materials can maintain 20% average purification efficiency. • We discussed the effects of distance, ozone concentration, and relative humidity. [ABSTRACT FROM AUTHOR]