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Abstract: A comprehensive study was carried out on amorphous metal‐organic frameworks Mn‐MIL‐100 as efficient catalysts for CO oxidation. This study focused on explaining the crystalline–amorphous–crystalline transformations during thermolysis of Mn‐MIL‐100 and studying the structure changes during the CO oxidation reaction. A possible formation mechanism of amorphous Mn‐MIL‐100 was proposed. Amorphous Mn‐MIL‐100 obtained by calcination at 250 °C (a‐Mn‐250) showed a smaller specific surface area (4 m2 g−1) but high catalytic activity. Furthermore, the structure of amorphous Mn‐MIL‐100 was labile during the reaction. When a‐Mn‐250 was treated with reaction atmosphere at high temperature (giving used‐a‐Mn‐250‐S), the amorphous catalysts transformed into Mn2O3. Meanwhile, the BET surface area (164 m2 g−1) and catalytic performance both sharply increased. In addition, used‐a‐Mn‐250‐S catalyst transformed from Mn2O3 into Mn3O4, and this resulted in a slight decrease of catalytic activity in the presence of 1 vol % water vapor in the feed stream. A schematic mechanism of the structure changes during the reaction process was proposed. The success of the synthesis relies on the increase in BET surface area by using CO as retreatment atmosphere, and the enhanced catalytic activity was attributed to the unique structure, a large quantity of surface active oxygen species, oxygen vacancies, and good low‐temperature reduction behavior. [ABSTRACT FROM AUTHOR]

A solvent-dependent oxidative dearomatization-induced divergent [5+2] cascade approach to bicyclo[3.2.1]octanes was described. This novel protocol enables a facile synthesis of a series of diversely functionalized ent-kaurene and cedrene-type skeletons in good yields and excellent diastereoselectivities. [ABSTRACT FROM AUTHOR]

Cu–Mn–Ce–O composites with enhanced surface area and developed mesoporosity were synthesized using a homogeneous coprecipitation (hcp) method, and were tested in the catalytic destruction of chlorobenzene (CB). X-ray diffraction (XRD), N 2 adsorption/desorption, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), temperature programmed reduction (H 2 -TPR), temperature programmed desorption of CB/O 2 (CB/O 2 -TPD), and diffuse reflectance ultraviolet visible spectroscopy (DRUV-Vis) were used to characterize the structure and textural properties of catalysts. Mn and Cu enter CeO 2 matrix with a fluorite-like structure, and produce large amounts of oxygen vacancies. Addition of manganese promotes the formation of reduced copper phase, and the presence of large numbers of high valence Mn 4+ ions strongly enhances the redox couple of Cu + –Cu 2+ in the composites. Both the synthesis protocol and metal doping amount significantly affect the catalyst reducibility, surface state and oxygen density. Cu 0.15 Mn 0.15 Ce 0.85 O x synthesized via the hcp method exhibits the highest catalytic activity with 90% of chlorobenzene destructed at 255 °C (CO 2 selectivity > 99.5%). Enriched surface oxygen, excellent active oxygen mobility and CB adsorption ability guarantee the superior activity and stability of Cu–Mn–Ce–O composite catalysts. Nucleophilic and electrophilic substitutions happen in sequence during chlorobenzene destruction, and the adsorbed Cl can be finally removed in the form of Cl 2 via the Deacon reaction. Furthermore, the incorporation of CuO and MnO x phases can inhibit the formation of organic byproducts, such as phenolates, maleates, and o -benzoquinone-type species, especially at elevated reaction temperatures. [ABSTRACT FROM AUTHOR]

Abstract: A series of micro/mesoporous hybridized materials with coke-resistant ZSM-5 and three-dimensional large pore KIT-6 as their micro- and mesoporous components were synthesized and investigated for toluene deep oxidation. The characterization results show that most of Al atoms are tetrahedrally coordinated in the framework of the samples, and the ratio of ZSM-5 to KIT-6 can be systematically controlled by varying the Si/Al molar ratio in the synthesis mixture. The acid sites over the supports are favorable for Pd nanoparticle dispersion and metallic Pd oxidation due to their electrophilic characters. All Pd supported composite materials are found to be powerful catalysts for the total oxidation of toluene. Particularly, Pd/ZK-50 possesses the highest catalytic activity with 90% toluene decomposition at 197°C, this temperature is much lower than that of Pd/KIT-6 (T 90 =234°C). CO2 desorption capability has positive effects on catalytic activity, while the influence of toluene adsorption property is negligible. The superior activity of the composite catalysts can be ascribed to the cumulative of specific surface area, support acidity, Pd particles dispersion and CO2 desorption capability. [Copyright &y& Elsevier]

Abstract: Short column SBA-15 supported Pd mesoporous catalysts with controllable acidity and expanded microporosity were firstly prepared through a simple “two-solvents” approach. The catalytic performances of the synthesized catalysts were evaluated for toluene oxidation. The characterization results reveal that Al atoms prefer to be tetrahedrally coordinated in the framework of the synthesized materials, and the acid sites can significantly promote Pd particle dispersion and metallic Pd oxidation due to their electrophilic characters. The Pd-confined catalysts possess high toluene turnover frequencies and toluene can be totally converted to CO2 and H2O below 210°C. The oxidation reaction can be suppressed by water vapor due to the formation of inactive Pd-hydroxides, and the synthesized catalyst has a good hydrothermal stability and high tolerance to moisture. Both the specific surface area and the toluene adsorption/desorption property are not the main factors determining the catalytic activity. Overall, the toluene oxidation performance is closely related to the support microporosity and acidity, the Pd dispersion and the CO2 desorption capability. [Copyright &y& Elsevier]

Abstract: A series of novel Pd/Co3AlO catalysts derived from hydrotalcite-like compounds (HTlcs) have been prepared and investigated for total oxidation of toluene. The HTlcs phase Co–Al precursors were prepared by coprecipitation method and Pd active species were introduced by different approaches, i.e., impregnation (IMP), wet ion exchange (WIE) or directly at coprecipitation stage (COP). It is found that all hydrotalcite-derived Pd/Co3AlO catalysts are much more active than the Pd/Co3AlO catalyst prepared via traditional thermal combustion method (TCB) in toluene elimination. The activities of all synthesized catalysts obey the following sequence: Pd/Co3AlO (COP)>Pd/Co3AlO (WIE)≥Pd/Co3AlO (IMP)>Pd/Co3AlO (TCB). Excellent catalytic activities of the novel hydrotalicite-derived Pd/Co3AlO catalysts could be contributed to their high surface area, small mean crystallized size of support and highly dispersed PdO particles. Besides, they are well positively associated with catalyst reducibilities and the amounts of oxygen vacancies. According to the XPS, TEM and TPR results, it was found that the strong synergistic effect between Co3O4 and PdO, but not the amount of the surface palladium species which are generally believed to be the active sites, is the main factors determining the catalytic activity in this work. The stability tests indicate that all Pd/Co3AlO catalysts have no obvious deactivation, and some catalysts even show improved activities during the reaction process due to the emergence of metal Pd. [ABSTRACT FROM AUTHOR]

Abstract: In this study, mesoporous SBA-15 supported Pd catalysts were synthesized through impregnation and grafting approaches. Moreover, the influences of different solvents (ethanol, H2O, tetrahydrofuran, dimethyl sulphoxide and N,N-dimethylformamide) on the dispersion of supported Pd nanoparticles were also systematically investigated. The prepared materials were comprehensively explored by various techniques, including XRD, EDS, ICP-OES, H2 chemisorption, N2 adsorption/desorption, TG-DSC, FT-IR, TEM and STEM. It is found that the traditional impregnation method has some disadvantages in obtaining highly dispersed Pd active phase. Whereas, the grafting method could highly disperse Pd nanoparticles within the mesoporous channels of support material, and the grafting procedure should be promising in designing highly dispersed Pd particles on the silica-based mesoporous materials. The catalyst prepared via the grafting procedure possesses much higher activity and selectivity than that prepared by impregnation method for deep catalytic oxidation of toluene. [Copyright &y& Elsevier]

Abstract: ZSM-5/MCM-48 composite materials with different acidities and enhanced thermal stability have been synthesized via a simple and reliable in situ overgrowth method. The as-prepared biporous materials and the Pd-impregnated catalysts were systematically investigated by various techniques, including XRD, ICP-OES, N2 adsorption/desorption, H2 chemisorption, SEM, TEM/HRTEM, FT-IR, 27Al MAS NMR, NH3-TPD, H2-TPR and XPS. The characterization results reveal that all composite catalysts exhibit high surface area, large pore volume and long pore diameter. The quantity of acid sites increases as the ZSM-5 additive amount increases, and Al atoms are in the tetrahedral coordination positions in composite materials. The activity tests demonstrate that all the Pd-loaded catalysts are active in the total elimination of benzene, while the catalytic activity values of Pd-loaded ZSM-5/MCM-48 composite catalysts are much higher than those of Pd/ZSM-5 or Pd/MCM-48 alone. Both Pd0 and Pd2+ are responsible for the oxidation reaction, and the catalytic activities are primarily related to the support acidity and the Pd dispersion. In addition, the stability of the composite catalysts also improves with an appropriate amount of ZSM-5 additives in MCM-48. This research shows that the novel Pd-loaded composite catalysts are promising materials in the elimination of VOCs. [Copyright &y& Elsevier]

Abstract: ZSM-5/MCM-48 composite materials with various acidities have been successfully assembled on zeolite seeds via a two-step crystallization process. The characterization results reveal that the ZSM-5 seeds are present in the framework of the resulting composite materials with its content gradually increasing with the Si/Al molar ratio, and Al atoms prefer the tetrahedral coordination in composite products. The amount of strong acid sites increases as the Si/Al molar ratio decreases, while that of weak acid sites is almost unchanged. The activity tests demonstrate that the catalytic activity of Pd-loaded ZSM-5/MCM-48 composite catalysts is much higher than that of Pd/ZSM-5 and Pd/MCM-48, and all these catalysts are active and stable in the total oxidation of benzene. Both Pd0 and Pd2+ are responsible for the oxidation reaction, and the catalytic activity is closely related to the support acidity, the CO2 desorption capability and the Pd dispersion. This research thus indicates that the novel composite materials have promised as active Pd-supported catalysts in the elimination of volatile organic compound (VOCs). [Copyright &y& Elsevier]

The feasibility and mechanism of five molecular sieves-supported palladium catalysts in elimination of benzene, toluene, and ethyl acetate were investigated. The experimental results indicate that Pd particles are well dispersed on these porous supports with size of 2−10 nm, while mesoporous supports with a larger specific surface area and pore diameter lead to a better dispersion. The activity of freshly made catalysts obeys the following order: Pd/Beta > Pd/ZSM-5 > Pd/SBA-15 > Pd/MCM-48 > Pd/MCM-41. Although Pd/Beta has the highest activity for removal of these VOCs in the beginning, its activity quickly decreases. However, Pd/ZSM-5 and Pd/SBA-15 show a good stability, without activity loss in a 72 h test. Our research reveals that higher acidity can facilitate catalytic reaction and gives rise to higher activity, but it also enhances coke formation and decreases the catalyst stability. In addition, the porosity of supports has a certain impact on catalytic oxidation of VOCs. [ABSTRACT FROM AUTHOR]

[Display omitted] • CuO x /MnO 2 catalysts with different crystal phases of MnO 2 were synthesized. • CuO x / α-MnO 2 catalyst showed excellent catalytic activity in NO reduction and CO oxidation. • The presence of CO enhanced the NH 3 -SCR catalytic activity of catalyst. • Mechanism model for NO reduction and CO oxidation was proposed. NO and CO are two primary pollutants in the sintering flue gas emission, posing significant challenges for the treatment. Under oxygen-enriched conditions, CO was easily oxidized to CO 2 before participating in CO-SCR reaction as a reducing agent. Consequently, NH 3 -SCR technology coupled with CO oxidation reaction is a promising approach for simultaneous NO and CO removal. In this study, a series of bifunctional CuO x /MnO 2 catalysts were synthesized using a combine of hydrothermal and wet impregnation methods, and their catalytic performance for simultaneous removal of NO and CO was assessed. CuO x /α-MnO 2 catalyst displayed outstanding catalytic activity for both NO and CO, achieving over 80 % NO removal efficiency and 96 % CO conversion rate at 150 °C, while CuO x /β-MnO 2 catalyst exhibited poor catalytic activity in the entire temperature range. Moreover, the interplay between the NH 3 -SCR and CO catalytic oxidation reactions was also explored. XPS results revealed that the concentration of Mn4+ and Cu+ species significantly influenced the catalytic activity of the catalysts for the simultaneous removal of NO and CO. Particularly, the presence of Mn4+ species promoted "fast SCR" reaction, whereas Cu+ species demonstrated higher reactivity for both NO reduction and CO oxidation. In situ DRIFTS analysis of transient reactions revealed that the L-H mechanism was followed over CuO x /α-MnO 2 catalyst in the NH 3 -SCR reaction, while both the M-K and L-H mechanisms were observed in CO catalytic oxidation reaction. [ABSTRACT FROM AUTHOR]

Pt/TiO 2 catalysts with various Pt loadings (0.1–0.7 wt.%) were synthesized by a combined wet impregnation and H 2 -reduction method. The as-prepared catalysts were firstly reported being applied in thermal catalytic decomposition of hydrogen peroxide (H 2 O 2 ) vapor for treating NO X . Physico-chemical properties of Pt/TiO 2 catalysts were investigated by comprehensive techniques, including XRD, Raman, N 2 adsorption–desorption, TEM, UV–vis DRS, XPS and PL spectroscopy. The activity tests showed that the incorporation of platinum into TiO 2 led to a significant increase in the catalytic oxidation of NO compared with the unmodified TiO 2 . Toward NO oxidation from H 2 O 2 vapor (molar ratio = 12/1), 0.3 wt.% Pt-TiO 2 exhibited a remarkable activity in NO X removal (96.7%) and a high selectivity (89.2%) in their conversion to nitrate species under the optimal condition. XRD and TEM results show that ultrafine Pt particles were well dispersed on the surface of anatase-phase TiO 2 . XPS analysis indicated that Pt dopant existed as mainly metallic Pt (0) and a small portion of Pt 2+ in as-prepared materials. The results of PL spectra demonstrated that the platinum nanoparticles on the TiO 2 surface significantly accelerated electron transfer and served as active sites for the adsorption and activation of H 2 O 2 molecules, to facilitate the generation of hydroxyl groups. [ABSTRACT FROM AUTHOR]

Reactivity loss by intermediates aggregation and water vapor inhibition are two major and longstanding challenges for the noble-metal-based catalysts in oxygenated volatile organic compounds (OVOCs) oxidation. Herein, the core-shell Pd@CoO Janus sites are creatively designed and stabilized over the HSAPO-34 support. Quasi in situ XPS spectra reveal that the strong interactions in Pd@CoO Janus sites promote the charge redistribution and electron back-donation through Pd-O-Co coordination. Therefore, abundant positively charged Pd2+ sites are formed and oxygen species transformation is facilitated, which significantly promote the low-temperature efficiency of acetone oxidation. Furthermore, the Pd@CoO/HSAPO-34 catalyst facilitates H 2 O molecules dissociation and produce reactive OH Ter and OH Tri species, which considerably promotes the rapid decomposition of aldehyde intermediate via attacked CH 2 O* group, ensuring low-temperature oxidation of acetone. This work provides valuable guidance to develop specific catalysts with functional active sites for rationally utilizing H 2 O molecules to improve low-temperature performance and modulate reaction pathways during OVOCs oxidation. [Display omitted] • Thermal-depolymerization was employed to synthesize the Pd@CoO Janus sites. • Charge redistribution through Pd-O-Co coordination facilitates reactant activation. • Positively charged Pd2+ and activated Co-O coordination promote acetone oxidation. • Pd@CoO/HSAPO-34 catalyst facilitates the dissociation of H 2 O molecules. • Surface OH Tri and OH Ter groups accelerate aldehyde intermediate degradation. [ABSTRACT FROM AUTHOR]

Abstract: High quality nanosize Al-HMS was successfully synthesized using ethanol as the co-solvent. Pd atoms could be highly dispersed on this nanosize support with ordered size of ca.12nm. TEM studies revealed that support size could influence Pd dispersion behaviors greatly. Besides, frame Al of support also played some positive role on the catalytic activity of Pd-loaded catalyst. The complete conversion of benzene could be got at 200°C on this nanosize Pd/Al-HMS catalyst loaded only 0.9wt% Pd under high gas hourly space velocity of ca.100000h−1. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • CrO x /LaSrMnCoO 6 (Cr/LSMC) composite catalysts were rationally designed. • Obvious synergistic effect between CrO x and LSMC can be observed. • 10 wt.% Cr/LSMC has excellent catalytic stability and H 2 O resistance. • By-products distribution during 1,2-dichloroethane oxidation was studied. Abstract 1,2-dichloroethane (1,2-DCE) is a representative industrial chlorinated volatile organic compound (CVOC) making great hazardous to the environment and human health. In this work, LaSrMnCoO 6 (LSMC) double perovskite-type materials with high thermal stability and coke resistance in 1,2-DCE oxidation were prepared by a facile sol-gel method. Based on this, a series of CrO x /LaSrMnCoO 6 catalysts (Cr/LSMC, CrO x loading = 5 to 20 wt.%) which combine the merits of CrO x (high activity and chlorine tolerance) and LaSrMnCoO 6 were synthesized and adopted in deep oxidation of 1,2-DCE for the first time. As expected, obvious synergistic effects between CrO x and LSMC on 1,2-DCE destruction were observed. Amongst, 10 wt.% CrO x /LaSrMnCoO 6 (10Cr/LSMC) shows the best catalytic activity with 90% of 1,2-DCE destructed at 400 °C. Furthermore, the outstanding catalytic durability and water resistance of 10Cr/LSMC in 1,2-DCE oxidation were also demonstrated. In addition to this, the reaction pathway of 1,2-DCE decomposition over Cr/LSMC materials was discussed based on the results of online product analysis. We found that the enhanced catalytic performance of Cr/LSMC materials can be reasonably attributed to their high reducibility, excellent 1,2-DCE adsorption capability, and large amounts of surface active lattice oxygen species. It can be anticipated that the Cr/LSMC catalysts are promising materials for CVOC elimination and the results from this work could also provide some new insights into the design of catalysts for CVOC efficient destruction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Short rod-like micro-mesoporous composite SBA-15 (SBA-15-r) was rationally prepared. • Highly active SBA-15-r confined Pd materials were successfully synthesized. • Pd/S-5 possesses the best n -butylamine oxidation activity and lowest NO x yield. • Structural micropores play an important positive role in NO x formation control. • The n -butylamine destruction route and mechanism were proposed. Catalytic destruction of nitrogen-containing volatile organic compounds (NVOCs) is rarely reported although they can make great harm to the environment and public health. In the present work, a series of short rod-like micro-mesoporous composite SBA-15 materials (SBA-15-r) with developed porosity and enhanced mass transfer performance were rationally designed and synthesized, and highly dispersed and thermally stable Pd nanoparticles were successfully introduced into the mesopore channels of SBA-15-r via an extraordinary incipient wetness impregnation with the assistance of furfuryl alcohol and trimethylbenzene. The correlation between catalyst property and catalytic performance in n -butylamine destruction was elucidated. 29Si MAS NMR and FT-IR results show that phosphorus is incorporated into the skeleton of SBA-15-r through a P O Si connection, altering the structural property of support. All Pd/SBA-15-r materials are highly active and stable catalysts with n -butylamine totally converted at 280 °C. Amongst, Pd/S-5 possesses the best n -butylamine oxidation activity and lowest NO x formation rate ascribable to the largest surface area and highest porosity which can promote the dispersion of Pd active sites and accelerate the oxidation process and product diffusion, inhibiting the formation of reaction byproducts. Moreover, the structural micropores over Pd/SBA-15-r catalysts play an important positive role in NO x formation control. The n -butylamine destruction mechanism were further discussed according to the results of gas chromatography and in situ DRIFTS. We believe that the present work provides new insights into the design and application of high-efficient catalysts based on hierarchical materials in NVOC elimination. [ABSTRACT FROM AUTHOR]

In this study, g-C 3 N 4 nanosheets coated UiO-66 nanohybrids were fabricated via a simple solvothermal method. The physicochemical parameters, structural and electrochemical properties of g-C 3 N 4 /UiO-66 nanohybrids (CNUO-x) were investigated. The nanohybrids were systematically characterized by XRD, FT-IR, TGA, TEM, SEM, EDS elemental mappings, XPS, N 2 adsorption-desorption isotherms, PL and DRS. It was found that the addition of moderate g-C 3 N 4 could enhance the separation and migration rate of photo-induced charges, consequently leading to the increase of photocatalytic efficiency. The CNUO-1 nanohybrid exhibited better photocatalytic activity for the oxidation of Rh B under visible light irradiation, and displayed about 6.0 and 3.3 times faster than that of g-C 3 N 4 and UiO-66, respectively. Meanwhile, the nanohybrid showed excellent stability and reusability in four cyclic experiments. Finally, the increased photocatalytic reaction mechanism was also proposed. O 2 − , h + and OH were further found to be the main active contributors. [ABSTRACT FROM AUTHOR]

Mn3O4, FeMnO x , and FeO x catalysts synthesized via a solvothermal method were employed for catalytic oxidation of methyl-ethyl-ketone (MEK) at low temperature. Mn3O4 with sphere-like morphology exhibited the highest activity for MEK oxidation, over which MEK was completely oxidized to CO2 at 200 °C, and this result can be comparable to typical noble metal loaded catalysts. The activation energy of MEK over Mn3O4 (30.8 kJ/mol) was much lower than that of FeMnO x (41.5 kJ/mol) and FeO x (47.8 kJ/mol). The dominant planes, surface manganese species ratio, surface-absorbed oxygen, and redox capability played important roles in the catalytic activities of catalysts, while no significant correlation was found between specific surface area and MEK removal efficiency. Mn3O4 showed the highest activity, accounting for abundant oxygen vacancies, low content of surface Mn4+ and strong reducibility. The oxidation of MEK to CO2 via an intermediate of diacetyl is a reaction pathway on Mn3O4 catalyst. Due to high efficiency and low cost, sphere-shaped Mn3O4 is a promising catalyst for VOCs abatement. [ABSTRACT FROM AUTHOR]

Abstract: Au/HMS catalysts are prepared by impregnation method and direct synthesized method and evaluated for the selective oxidation of benzyl alcohol. Among all the catalysts studied, Au/HMS catalyst prepared by impregnation method exhibits the best activity, the benzyl alcohol conversion of 42.9% and benzaldehyde selectivity of 95% can be achieved at 80°C, 1atm O2 and existence of Na2CO3 aqueous solution. The Au/HMS catalysts are characterized by low-angle X-ray diffraction (XRD), wide-angle XRD, N2 adsorption/desorption and transmission electron microscopy (TEM) techniques. The effects of prepared method, gold particle size and HMS structure are investigated in detail. The active phase of gold catalysts for selective oxidation of benzyl alcohol is explored based on the catalytic performance and characterization results. Moreover, the possible activation mechanism for selective oxidation of benzyl alcohol on Au/HMS catalysts is studied by means of CO and O2 adsorption in situ diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS). [ABSTRACT FROM AUTHOR]

[Display omitted] • A series of transition metal cordierite-based monolithic catalysts were prepared. • Mn/Al 2 O 3 /COR shows excellent ethyl acetate (EA) oxidation activity and water resistance. • Surface oxygen species (O β) play vital roles in EA activation and intermediate generation. • Low content water vapor (≤1 vol%) promotes EA activation and ethanol formation. • Water vapor leads to the decline of O β and formation of large-size hard coke. The reduction and control of VOCs from anthropogenic sources becomes a research hotspot due to their tremendous environment hazards. Fabricating efficient and applicable noble-metal-free monolithic catalysts is still a great challenge for industrial VOC economical removal. In this work, cordierite-based honeycomb monolithic catalysts (M/Al 2 O 3 /COR; M = Cr, Mn, Fe, Co, Ni and Cu) were synthesized by a versatile and scalable wash-coating method and adopted for ethyl acetate (EA) catalytic oxidation. Mn/Al 2 O 3 /COR possesses remarkable activity with 90% of ethyl acetate (EA) oxidized at 236 °C owing to abundant surface active oxygen species. Moreover, excellent stability and water resistance of Mn/Al 2 O 3 /COR were observed during long-term successive reaction. In situ DRIFTS results reveal that the decomposition of EA to ethanol is the main pathway under humid conditions, and the presence of low content water vapor (≤1 vol%) promotes EA conversion ascribed to the presence of abundant OH derived from H 2 O dissociation; however, further increasing of water concentration inhibits EA conversion. The adsorption of OH over oxygen vacancies inhibits the generation of surface oxygen species and blocks further oxidation of intermediates to form acetate, leading to the reduction of CO 2 yield and formation of coke aggregates. This work will provide instructive and feasible references for designing of VOC oxidation catalysts under practical reaction conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mn-Cu bimetallic catalysts were facilely prepared by one-step hydrothermal-redox method. • Hydrothermal-redox was superior to other preparation methods for Mn-Cu catalysts. • MnCu spinel type catalyst exhibited excellent low-temperature catalytic performance. • PTR-MS results revealed the reaction routes of toluene oxidation over MnCu catalyst. Developing facile preparation method to obtain the satisfied low-temperature catalytic performance of transitional metal oxide-based materials is still a challenge in deep degradation of VOCs. Here, a series of Mn-Cu bimetallic oxide catalysts were prepared by one-step hydrothermal-redox method for catalytic total oxidation of toluene. The CH 3 COOH concentration, Cu/Mn molar ratio and calcination temperature greatly affected the crystal structure, micromorphology and catalytic performance. Amongst, MnCu spinel structured catalyst exhibited excellent low-temperature catalytic activity, superior durability and water resistance in toluene total oxidation owing to its abundant surface adsorbed oxygen species, higher amount of Cu+ and Mn3+ and excellent low-temperature reducibility. The reaction rate of MnCu was 7.0 times higher than that of MnCu 0.5 at 210 °C. The cyclic redox process with enough oxygen vacancy played a vital role in toluene oxidation. The deep oxidation of benzene was the key step in the toluene oxidation. Proton transfer reaction-mass spectrometry (PTR-MS) results revealed the reaction intermediates including benzaldehyde, benzene and phenol, which further decomposed to acetone, ethanol, acetic acid, ketone and acetaldehyde by ring opening before total mineralization. Therefore, PTR-MS provided a facile method to investigate the reaction mechanism of toluene oxidation. [ABSTRACT FROM AUTHOR]