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Non-precious metal catalysts with enhanced low-temperature activity and improved water resistance are highly demanded for emission control. CuO-based catalysts are promising alternatives to precious metal catalysts due to their acceptable activity and cost-effectiveness. However, there is an urgent need to further enhance their low-temperature activity and water resistance for industrial applications. Herein, CuO catalysts supported by various SiO2-TiO2 supports were prepared and evaluated for CO oxidation and NO reduction by CO reactions under the testing conditions with and without water. Among the studied catalysts with different SiO2 contents, CuO/5SiO2-TiO2, in which CuO was supported by SiO2-TiO2 with 5 wt.% SiO2, exhibited the best performance for CO oxidation. Compared with CuO/TiO2 and CuO/SiO2 reference catalysts, the CuO/5SiO2-TiO2 catalyst showed enhanced catalytic activity in both CO oxidation and NO reduction by CO under dry and wet conditions. Comprehensive characterizations revealed that the presence of SiO2 in TiO2 support facilitated the CuO/5SiO2-TiO2 catalyst with a high dispersion and reduced oxidation states of CuOx species. This not only improved the low-temperature reducibility but also enhanced the adsorption of reactive CO species. As a result, the CuO/5SiO2-TiO2 catalyst demonstrated superior catalytic activity. Furthermore, the inclusion of SiO2 in the catalyst inhibited H2O adsorption, contributing to the enhanced water resistance on CuO/5SiO2-TiO2 catalyst. These advantages in catalytic activity and water resistance make CuO/5SiO2-TiO2 a promising candidate for applications in emission control. [ABSTRACT FROM AUTHOR]

Non-precious metal catalysts with enhanced low-temperature activity and improved water resistance are highly demanded for emission control. CuO-based catalysts are promising alternatives to precious metal catalysts due to their acceptable activity and cost-effectiveness. However, there is an urgent need to further enhance their low-temperature activity and water resistance for industrial applications. Herein, CuO catalysts supported by various SiO2-TiO2 supports were prepared and evaluated for CO oxidation and NO reduction by CO reactions under the testing conditions with and without water. Among the studied catalysts with different SiO2 contents, CuO/5SiO2-TiO2, in which CuO was supported by SiO2-TiO2 with 5 wt.% SiO2, exhibited the best performance for CO oxidation. Compared with CuO/TiO2 and CuO/SiO2 reference catalysts, the CuO/5SiO2-TiO2 catalyst showed enhanced catalytic activity in both CO oxidation and NO reduction by CO under dry and wet conditions. Comprehensive characterizations revealed that the presence of SiO2 in TiO2 support facilitated the CuO/5SiO2-TiO2 catalyst with a high dispersion and reduced oxidation states of CuOx species. This not only improved the low-temperature reducibility but also enhanced the adsorption of reactive CO species. As a result, the CuO/5SiO2-TiO2 catalyst demonstrated superior catalytic activity. Furthermore, the inclusion of SiO2 in the catalyst inhibited H2O adsorption, contributing to the enhanced water resistance on CuO/5SiO2-TiO2 catalyst. These advantages in catalytic activity and water resistance make CuO/5SiO2-TiO2 a promising candidate for applications in emission control. [ABSTRACT FROM AUTHOR]

With the introduction of potassium species, the catalytic oxidation performance over the Pt1/CeO2 catalyst was significantly enhanced, where potassium ions acted as structural and electronic promoters, and formed Pt–O–K interactions with Pt to directly regulate the coordination environment and electronic state of Pt and the metal-support interaction between Pt and CeO2. [ABSTRACT FROM AUTHOR]

Due to the capacity to offer abundant catalytic sites within porous solids featuring high surface areas, metal-organic frameworks (MOFs) and their derivatives have garnered considerable attention as prospective catalysts in environmental catalysis. To promote the industrial application of MOFs, there is an urgent need for an effective and environmental-friendly preparation approach. Breaking through the limitation of the traditional two-step preparation method that Pd was introduced to the already prepared Ce-BTC (Pd/Ce-BTC, BTC = 1, 3, 5 benzenetricarboxylate), in this work, we present a novel one-pot solvothermal method for synthesizing the Pd material supported by Ce-BTC (Pd@Ce-BTC). After pyrolysis in N 2 flow or air flow, Pd-CeO 2 catalysts derived from Pd@Ce-BTC exhibited much higher CO oxidation activity than those from Pd/Ce-BTC. Moreover, Pd/Ce-BTC and Pd@Ce-BTC pyrolyzed in N 2 flow (Pd/Ce-BTC-N and Pd@Ce-BTC-N) could better catalyze the oxidation of CO than Pd/Ce-BTC and Pd@Ce-BTC pyrolyzed in air flow (Pd/Ce-BTC-A and Pd@Ce-BTC-A). Further characterizations revealed that the abundant surface Ce3+ species, rich surface adsorbed oxygen species and superior redox properties were the main reasons for the superior CO oxidation activity of Pd@Ce-BTC-N. [Display omitted] • A one-pot solvothermal method was developed for the preparation of Pd incorporated in Ce-BTC • The Pd-CeO 2 catalyst derived from one-pot generated Pd@Ce-BTC exhibited superior CO oxidation activity • The activity of the Pd-CeO 2 catalyst obtained through pyrolysis in nitrogen flow surpassed that obtained in air flow • High Pd dispersion and rich surface Ce3+ species contributed to the improved CO oxidation activity on Pd-CeO 2 [ABSTRACT FROM AUTHOR]

[Display omitted] • Small and uniform CeO 2 nanoparticles were prepared on Al 2 O 3 (CA-T) using a two-step incipient wetness impregnation method. • Pt single sites anchored to step sites of small CeO 2 entities within CA-T were more stable than those anchored to crystal surface of large CeO 2 particles on regular ceria-alumina. • The reactivity of CO adsorbed on Pt sites decreased by Pt cluster step sites ≈ Pt cluster terrace sites > Pt cluster corner sites ≫ Pt single sites on CeO 2. • Abundant Pt cluster step and terrace sites as well as rich Pt-CeO 2 interfaces facilitated the activated Pt/CA-T catalyst for efficient CO oxidation at low temperatures. In heterogeneous catalysis, the promotion of low temperature activity and enhancement of thermal stability simultaneously especially for precious metal catalysts is always highly demanded but very challenging. Herein we report a novel Pt catalyst on ceria-alumina (CeO 2 /Al 2 O 3) support (Pt/CA-T) engineered by a two-step ceria deposition strategy, exhibiting superior thermal stability and low-temperature carbon monoxide (CO) oxidation activity after activation. Pt single sites anchored to engineered CeO 2 edge sites are much more stable than that to CeO 2 (111) surface, and such stable single sites can be transformed into highly active Pt clusters for efficient low-temperature CO oxidation. Active site identification indicates that the CO oxidation activity of different Pt sites follows such sequence: Pt cluster step sites ≈ Pt cluster terrace sites > Pt cluster corner sites ≫ Pt single sites on CeO 2. The excellent low temperature activity of activated Pt/CA-T catalyst for CO oxidation is associated with its abundant Pt cluster step and terrace sites as well as rich Pt-CeO 2 interfaces, which facilitate the adsorption of active CO species and superior oxygen activation/transfer ability. The present study provides new insights into the structure–activity relationship of Pt-CeO 2 -Al 2 O 3 catalyst, which can also guide the preparation of other highly robust supported catalysts for important industrial applications. [ABSTRACT FROM AUTHOR]

To reveal the effect of ceria particle size on dispersion and structure of supported Pt catalysts during preparation, activation, and reaction testing, a unique CeO2/Al2O3 support (CA−c) with smaller CeO2 particle size and more surface defects was prepared using a colloidal CeO2 precursor, comparing with a conventional CeO2/Al2O3 support (CA−n) using cerium nitrate as precursor. More atomically dispersed Pt and abundant Pt−O−Ce structures were observed in the Pt/CA−c catalyst than in the Pt/CA−n catalyst. Both parent catalysts received significant enhancement on their catalytic CO oxidation activities if activated by 10% hydrogen at 400 °C before reaction. Between the two representative catalysts, the extent of activity enhancement upon activation was more pronounced for Pt/CA−c. We found that smaller Pt clusters with more active ionic Pt sites were generated on the activated Pt/CA−c catalyst, while agglomerated larger Pt particles with more metallic sites were formed on the activated Pt/CA−n. The facile formation of Ce3+ was also indicative of more active metal‐support interfaces in the activated Pt/CA−c catalyst. These results highlight the importance of regulating ceria support particles to enable a controlled anchoring and subsequent activation of Pt single atoms for low‐temperature CO oxidation reaction. [ABSTRACT FROM AUTHOR]

In this work, sulfation effect on NH3-SCR performance over CeO2 with different morphology (nanocubes and nanorods) was carefully studied. A morphology-sensitive sulfation effect on NH3-SCR activity was observed on CeO2. Interestingly, the NO removal efficiencies of CeO2 nanocubes and CeO2 nanorods got greatly enhanced after the sulfation at low-temperature range (< 350 °C). CeO2 nanorods exhibited a much higher NH3-SCR activity than that of CeO2 cubes. However, compared to CeO2 nanocubes, CeO2 nanorods suffered from a severe deactivation when sulfated at higher temperatures (> 350 °C). A series of characterizations such as N2 adsorption–desorption, XRD, HR-TEM, TG–DTA, Raman and in situ DRIFTS of SO2 + O2 adsorption were conducted to investigate the interactions between SO2 and nano-shaped CeO2. It was revealed that the morphology of CeO2 nanorods was damaged severely when sulfated at high temperature (> 350 °C), while the structure of CeO2 nanocubes was relatively stable under the same condition. Furthermore, more sulfate species were found on CeO2 nanorods than on CeO2 nanocubes, in particular of bulk like sulfate species. As a result, the NO removal efficiency of CeO2 nanorods declined greatly when sulfated at high temperature. [ABSTRACT FROM AUTHOR]

[Display omitted] • Single atom Pt catalysts are synthesized via the impregnation-pyrolysis method. • 0.5 Pt 1 /Fe 2 O 3 exhibits high photothermal catalytic activity for toluene removal. • The Vis-IR light plays a critical role for toluene complete oxidation. • Possible photothermal catalytic mechanism for toluene oxidation is proposed. • The solar light driven photothermal catalytic purification technique is developed. In this work, Fe 2 O 3 supported single atom Pt (x Pt 1 /Fe 2 O 3 , x = 0.25 and 0.5 wt%) catalysts (SACs) are synthesized via a novel and simple impregnation-pyrolysis method. HAADF-STEM images show that Pt is atomically dispersed on the surface of Fe 2 O 3. All samples exhibit good light-thermal conversion efficiency, which can increase the surface temperature of catalysts to 210 °C. The 0.5 Pt 1 /Fe 2 O 3 exhibits the best photothermal catalytic performance (the toluene conversion and CO 2 yield are 95 % and 87 %, respectively) for toluene oxidation under the irradiation of simulated sunlight with light intensity of 720 mW/cm2, which is attributed to its good light-thermal conversion efficiency and low temperature reducibility. The Vis-IR light plays a critical role in the photothermal catalytic oxidation of toluene in the whole solar spectrum. Furthermore, the possible photothermal catalytic reaction pathway of toluene oxidation is proposed based on the TD-GC/MS and in-situ DRIFTS experiments. [ABSTRACT FROM AUTHOR]

Supported 0.05 wt% Pt catalysts, prepared via an in situ molten salt method, show high catalytic activity for acetone removal. Ce-, V-, or W-doping increases the amount of surface acid sites, and then enhances H 2 O-, CO 2 -, and SO 2 -tolerance of 0.05 wt% Pt/TiO 2. The present Pt catalysts might be suitable for oxygenated VOCs removal. • Supported 0.05 wt% Pt catalysts are prepared using an in situ molten salt method. • Supported 0.05 wt% Pt catalysts show high catalytic activity for acetone removal. • Ce-, V-, or W-doping enhance H 2 O-, CO 2 -, and SO 2 -tolerance of 0.05 wt% Pt/TiO 2. • Surface acidity greatly influences SO 2 tolerance of supported 0.05 wt% Pt catalyst. • The present Pt catalysts might be suitable for oxygenated VOCs removal. Volatile organic compounds (VOCs) cause damage to atmospheric environment and human health. Supported noble metal catalysts are widely used to control VOCs emissions. The high cost, and low H 2 O-, CO 2 -, and SO 2 -resistance of such catalysts are worthy to be improved. Herein we fabricated Ce-, V-, or W-doped TiO 2 supported ultralow loading Pt catalysts via the in-situ molten salt method, and evaluated their catalytic performance for acetone (major pollutants in pharmaceutical industry) removal. Under the present reaction conditions, all the catalysts exhibited high catalytic activity and stability for acetone oxidation, with the temperature required 90% acetone conversion being of 245 °C over 0.57 wt% CeO 2 -0.05 wt% Pt/TiO 2. The doping of Ce, V, or W enhanced the H 2 O-, CO 2 -, and SO 2 -tolerance ability of 0.05 wt% Pt/TiO 2. More than 85 %85%, 70%, or 60% of acetone could be removed even in the presence of 20 vol% water vapor, 10 vol% CO 2 , or 100 ppm SO 2 , respectively. The improvement in SO 2 -tolerance ability was due to the inhibition of SO 2 adsorption and oxidation activity as well as Ti(SO 4) 2 or TiOSO 4 formation. Acetone complete oxidation over 0.57 wt% CeO 2 -0.05 wt% Pt/TiO 2 would follow the pathway: adsorbed acetone molecules → acetic acid and formic acid → carbonate species → CO 2 and H 2 O. The present supported Pt catalysts might be suitable for oxygenated VOCs removal. [ABSTRACT FROM AUTHOR]

Selective catalytic reduction (SCR) of NO x with NH 3 has been widely used for the removal of NO x. Because of the inevitable disadvantages of conventional V 2 O 5 -WO 3 (MoO 3)/TiO 2 catalysts such as poor low-temperature SCR activity and toxicity of vanadium, as well as the high-cost and over-strong NH 3 adsorption of zeolite catalysts, the development of efficient and non-toxic metal oxide SCR catalysts is highly demanded. Previously, we have developed an environmentally-benign CeO 2 -SiO 2 mixed-oxide SCR catalyst (CeSi 2), which exhibited superior SO 2 resistance ability. However, the low-temperature SCR activity on CeSi 2 was not that satisfactory. In this work, we proposed a new strategy of Mo doping to improve the low-temperature SCR activity on CeSi 2 , which was very crucial for its practical application. By a simple co-precipitation method, a homogenous Mo-Ce-Si mixed-oxide catalyst was prepared. The Mo doping could significantly enhance the NH 3 -SCR activity on CeSi 2 below 250 °C, and the optimal catalyst was Mo 0.1 CeSi 2 , which could achieve 80% NO x conversion at 200 °C. Mo 0.1 CeSi 2 also exhibited superior N 2 selectivity and resistance to SO 2 /H 2 O poisoning. Via a series of characterizations, it was found that the redox properties and surface acidity on CeSi 2 by Mo doping, which accounted for the enhanced low-temperature NH 3 -SCR activity on Mo 0.1 CeSi 2. The reaction mechanism on Mo 0.1 CeSi 2 was also fully revealed by in situ DRIFTS experiments. This work provided a new insight for the development of efficient low-temperature SCR catalysts with superior SO 2 resistance ability. [Display omitted] • A homogeneous Mo-Ce-Si mixed-oxide catalyst was prepared. • Enhanced low-temperature NH 3 -SCR activity was achieved on Mo doped CeO 2 -SiO 2. • Mo-Ce-Si catalyst exhibited excellent resistance to SO 2 poisoning. • Surface acidity and redox properties of CeO 2 -SiO 2 were promoted by Mo doping. • NH 3 -SCR reaction on Mo-Ce-Si catalyst proceeds through E-R mechanism. [ABSTRACT FROM AUTHOR]

Three-dimensionally ordered mesoporous Cr 2 O 3 ( meso -Cr 2 O 3 ) and its supported Au, Pd, and Au–Pd (0.90 wt% Au/ meso -Cr 2 O 3 , 1.00 wt% Pd/ meso -Cr 2 O 3 , and x Au 1 Pd 2 / meso -Cr 2 O 3 ( x = 0.50–1.95 wt%) catalysts were prepared using the KIT-6-templating and polyvinyl alcohol-protected reduction methods, respectively. Physicochemical properties of the samples were characterized by means of numerous techniques, and their catalytic activities were evaluated for the oxidation of toluene. It is found that the meso -Cr 2 O 3 with a high surface area of 74 m 2 /g was rhombohedral in crystal structure and the noble metal nanoparticles (NPs) with a size of 2.9–3.7 nm were uniformly dispersed on the surface of meso -Cr 2 O 3 . The 1.95Au 1 Pd 2 / meso -Cr 2 O 3 sample performed the best: the T 10% , T 50% , and T 90% (temperatures required for achieving toluene conversions of 10, 50, and 90%) were 87, 145, and 165 °C at a space velocity of 20,000 mL/(g h), respectively, and the apparent activation energy was the lowest (31 kJ/mol) among all of the samples. The effect of moisture on the catalytic activity of the 1.95Au 1 Pd 2 / meso -Cr 2 O 3 sample was also examined. It is concluded that the excellent catalytic performance of 1.95Au 1 Pd 2 / meso -Cr 2 O 3 was associated with its small Au–Pd particle size, high adsorbed oxygen species concentration, good low-temperature reducibility, and strong interaction between Au–Pd NPs and meso -Cr 2 O 3 . [ABSTRACT FROM AUTHOR]

Mesoporous manganese oxide (meso-MnO y) and its supported Co, Pt, and Pt x Co catalysts are prepared via the KIT-6-templating and PVA-protected reduction routes, respectively. The excellent catalytic activity of 0.70 wt% Pt 2.42 Co/meso-MnO y is associated with its highly dispersed Pt 2.42 Co alloy NPs, high adsorbed oxygen species concentration, good low-temperature reducibility, and strong interaction between Pt 2.42 Co NPs and meso-MnO y. • Pt x Co/meso-MnO y is prepared via the polyvinyl alcohol-protected reduction route. • Pt x Co alloy is formed in each of the Pt x Co/meso-MnO y samples. • 0.70 wt% Pt 2.42 Co/meso-MnO y performs the best for methanol combustion. • Pt x Co alloy, O ads content, reducibility, and metal-support interaction govern activity. The KIT-6-templating and polyvinyl alcohol-protected NaBH 4 reduction methods were adopted to prepare the mesoporous manganese oxide (meso-MnO y) and its supported Co, Pt, and Pt x Co catalysts, respectively. Numerous techniques were used to characterize the physicochemical properties of the materials. Catalytic performance of the samples was evaluated for methanol combustion. All of the samples possessed a three-dimensionally ordered mesoporous structure and a surface area of 94–110 m2/g. The Co, Pt, and Pt x Co nanoparticles (NPs) with an average size of 2.2–3.0 nm were uniformly dispersed on the surface of meso-MnO y. The 0.70 wt% Pt 2.42 Co/meso-MnO y sample performed the best: the T 50% and T 90% (temperatures required for achieving methanol conversions of 50 and 90%, respectively) were 50 and 86 °C at a space velocity of 80,000 mL/(g h). The partial deactivation of the 0.70Pt 2.42 Co/meso-MnO y sample due to water vapor or carbon dioxide introduction was reversible. It is concluded that the excellent catalytic activity of 0.70 wt% Pt 2.42 Co/meso-MnO y was associated with its highly dispersed Pt 2.42 Co alloy NPs, high adsorbed oxygen species concentration, good low-temperature reducibility, and strong interaction between Pt 2.42 Co alloy NPs and meso-MnO y. [ABSTRACT FROM AUTHOR]

Graphical abstract The x Co 3 O 4 –MnO 2 (x = 2.6–13.3 wt%) catalysts are prepared using the PMMA-templating, incipient wetness impregnation, and acid treatment methods. It is found that the good catalytic performance of 8.8Co 3 O 4 –MnO 2 is associated with its high O ads species concentration, good low-temperature reducibility, and strong interaction between Co 3 O 4 and MnO 2. Highlights • 3DOM LaMnO 3 is synthesized using the PMMA-templating method. • x Co 3 O 4 –MnO 2 is prepared by treating Co 3 O 4 /3DOM LaMnO 3 with nitric acid. • 8.8Co 3 O 4 –MnO 2 shows the highest catalytic activity for o -xylene combustion. • Activity is governed by O ads content, reducibility, and Co 3 O 4 –MnO 2 interaction. Abstract The x Co 3 O 4 –MnO 2 (x = 2.6, 8.8, and 13.3 wt%) catalysts were prepared using the polymethyl methacrylate microspheres-templating, incipient wetness impregnation, and acid treatment methods. Physicochemical properties of the samples were characterized by means of various techniques. Catalytic performance of the x Co 3 O 4 –MnO 2 samples was evaluated for the combustion of o -xylene. It is shown that the as-prepared samples possessed a cubic crystal structure and a surface area of 51.9–63.9 m2/g. The 8.8Co 3 O 4 –MnO 2 sample possessed the highest adsorbed oxygen species concentration and the best low-temperature reducibility, and hence performing the best: the T 10% , T 50% , and T 90% (temperatures required for achieving o -xylene conversion of 10, 50, and 90%, respectively) were 231, 251, and 273 °C at a space velocity of 100,000 mL/(g h). The apparent activation energies obtained over the x Co 3 O 4 –MnO 2 catalysts for o -xylene combustion were 72–82 kJ/mol. The effects of space velocity, water vapor, and carbon dioxide on the catalytic activity of the 8.8Co 3 O 4 –MnO 2 sample were also examined, and the partial deactivation due to water vapor and carbon dioxide introduction was reversible. It is concluded that the good catalytic performance of 8.8Co 3 O 4 –MnO 2 was associated with its high adsorbed oxygen species concentration, good low-temperature reducibility, and strong interaction between Co 3 O 4 and MnO 2. [ABSTRACT FROM AUTHOR]

Three-dimensionally ordered macroporous (3DOM) LaMnAl 11 O 19 and x AuPd y /3DOM LaMnAl 11 O 19 ( x = 0.44 − 1.91 wt%; y = 1.80 − 1.86) were prepared via the polymethyl methacrylate (PMMA)-templating and gas bubble-assisted polyvinyl alcohol (PVA)-protected reduction routes, respectively. Physicochemical properties of the samples were characterized by a number of analytical techniques. Catalytic activities of the samples were measured for methane combustion in a continuous-flow microreactor. It is shown that the LaMnAl 11 O 19 in each of the samples was hexagonal in crystal structure, and all of the samples possessed a good-quality 3DOM architecture with a surface area of 24.4 − 28.2 m 2 /g. The Au–Pd nanoparticles (NPs) with an average size of 2.8 nm were uniformly dispersed on the macropore walls of 3DOM LaMnAl 11 O 19 . The 1.91AuPd 1.80 /3DOM LaMnAl 11 O 19 sample performed the best for methane combustion ( T 50% = 342 °C and T 90% = 402 °C at a space velocity of 20,000 mL/(g h)). The deactivation of the 1.91AuPd 1.80 /3DOM LaMnAl 11 O 19 catalyst induced by water vapor introduction was reversible, whereas that induced by SO 2 addition was irreversible. It is concluded that the good catalytic activity of 1.91AuPd 1.80 /3DOM LaMnAl 11 O 19 was related to its good-quality 3DOM structure, highly dispersed Au–Pd NPs, high adsorbed oxygen species concentration, good low-temperature reducibility, and strong interaction between Au–Pd alloy NPs and 3DOM LaMnAl 11 O 19 . [ABSTRACT FROM AUTHOR]

Three-dimensionally ordered mesoporous Co 3 O 4 ( meso -Co 3 O 4 ) and its supported Au, Pd, and Au–Pd alloy ( x Au y Pd/ meso -Co 3 O 4 ; x = 0.43–2.94 wt%; Au/Pd molar ratio ( y ) = 0.43–0.50) nanocatalysts were prepared using the KIT-6-templating and polyvinyl alcohol-protected reduction methods, respectively. It is found that the meso -Co 3 O 4 with a high surface area of 106 m 2 /g was cubic in crystal structure and the noble metal nanoparticles (NPs) with a size of 2.7–4.5 nm were uniformly dispersed on the surface of meso -Co 3 O 4 . The 2.94Au 0.50 Pd/ meso -Co 3 O 4 sample performed the best for methane combustion, showing the T 10% , T 50% , and T 90% (temperatures required for achieving methane conversions of 10%, 50%, and 90%) of 230, 280, and 324 °C at a space velocity of 20,000 mL/(g h) and the lowest apparent activation energy of 44.4 kJ/mol. Furthermore, the effects of CO 2 , SO 2 , and H 2 O addition on the catalytic stability of 2.94Au 0.50 Pd/ meso -Co 3 O 4 were also examined. It is concluded that the excellent catalytic performance of 2.94Au 0.50 Pd/ meso -Co 3 O 4 was associated with its porous structure, high adsorbed oxygen species concentration, good low-temperature reducibility, and strong interaction between Au–Pd alloy NPs and meso -Co 3 O 4 . [ABSTRACT FROM AUTHOR]

Highlights: [•] High-surface-area 3DOM La0.6Sr0.4MnO3 is prepared by the PMMA-templating method. [•] Surfactant addition is critical in 3DOM structure formation with nanovoid-like walls. [•] The calcination procedure is a key step in the formation of 3DOM structure. [•] 3DOM La0.6Sr0.4MnO3-DP3 performs best in the combustion of methane. [•] Surface area, Oads, and reducibility determine the activity of 3DOM La0.6Sr0.4MnO3. [Copyright &y& Elsevier]

Understanding the nature of active sites on metal oxide catalysts in the selective catalytic reduction (SCR) of NO by NH 3 (NH 3 -SCR) is a crucial prerequisite for the development of novel efficient NH 3 -SCR catalysts. In this work, two CeO 2 -based SCR catalyst systems with diverse acidic metal oxides-CeO 2 interfaces, i.e., Nb 2 O 5 -CeO 2 (Nb 2 O 5 /CeO 2 and CeO 2 /Nb 2 O 5) and WO 3 -CeO 2 (WO 3 /CeO 2 and CeO 2 /WO 3), were prepared and used to reveal the relationship between NH 3 -SCR activity and surface acidity/redox properties. In combination with the results of the NH 3 -SCR activity test and various characterizations, it was found that the NH 3 -SCR performance of Nb 2 O 5 -CeO 2 and WO 3 -CeO 2 catalysts was highly dependent on the strong interactions between the redox component (CeO 2) and acidic component (Nb 2 O 5 or WO 3), as well as the amount of paired redox-acid sites. From a quantitative perspective, an activity-surface acidity/redox property relationship was proposed. For both Nb 2 O 5 -CeO 2 and WO 3 -CeO 2 catalysts systems operated at the more concerned low-temperature range (200 °C), the NH 3 -SCR activity in low NO x conversion region (< 40%) was mainly dominated by the surface acidity of catalysts, while the NH 3 -SCR activity in high NO x conversion region (> 40%) was more determined by redox properties. [Display omitted] • Nb 2 O 5 -CeO 2 and WO 3 -CeO 2 catalysts with tuned redox-acid property were synthesized. • Paired redox-acid sites formed through strong interaction between Nb 2 O 5 /WO 3 and CeO 2. • NH 3 -SCR activity was well controlled by the paired redox-acid sites. • Surface acidity and redox property were investigated from a quantitative perspective. • A clear surface acidity/redox property-activity relationship was established. [ABSTRACT FROM AUTHOR]