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A series of unsupported and supported vanadium phosphorus oxide catalysts were prepared by employing a new strategy, which significantly reduced the complexity of catalyst preparation. The greatly simplified catalyst fabrication benefits a greener and lower-cost process for practical applications. The currently fabricated systems showed ca. 90% target product(s) selectivity with a promising yield as well as catalyst durability. [ABSTRACT FROM AUTHOR]

The interactions between the reactants and catalysts surfaces play a significant role in heterogeneous catalysis, thus to tune the interfacial properties between them has emerged as an important topic. This review has summarised some recent advances about the effects of wettability on the catalytic reactions, including hydrophilicity, hydrophobicity, and dewetting properties. In addition, the effect of coalescence dynamics among the catalyst particles is also discussed based on a series of investigations. Although the researchers have realised the importance of wettability, the ability to tune the wettability in their work needs to be further enhanced. Therefore, we finally highlighted considerable useful approaches to achieve controllable wettability and coalescence. It is expected that in the future design of catalysts, researchers should pay more attention to tuning the interfacial structure to achieve the enhanced catalysts behaviours. Wet wet wet: Surface wettability and coalescence dynamics have a great impact on the catalyst activity and the preparation of catalyst, and the catalytic performances could be significantly improved by the fine control of surface wettability and coalescence dynamics. Here, the authors provide many effective approaches to achieve the controllable surface wettability and coalescence, which is expected to be applied in the catalytic field. [ABSTRACT FROM AUTHOR]

Abstract: The rational design of low‐cost transition metal catalysts that exhibit high activity and selectivity may be the most significantly investigated in heterogeneous catalysis. In this study, Co3‐xMnxO4 (x=0.75, 1.0, and 1.5) mixed metal oxides were successfully synthesized by a controlled template‐free autoclave strategy and studied for toluene oxidation. It is found that the Co‐rich sample showed markedly enhanced activity and the 3D dandelion‐like Co2.25Mn0.75O4 catalyst exhibited in the highest toluene oxidation rate (8.9 μmol/(gcats)) and a 100 % toluene conversion at 239 °C. In situ DRIFTS study indicates that toluene was sequentially oxidized to benzyl radical, benzaldehyde, benzene, oxalic acid, and finally to CO2 and H2O. The interaction between Co and Mn, in conjunction with the high concentration of surface oxygen species and rich surface oxygen vacancies, reasonably explains the elevated catalytic activity and thermal stability for toluene oxidation over 3D flower‐like Co3‐xMnxO4 spinel catalysts. [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]

A series of novel metal-oxide-supported CeO2 catalysts were prepared via the wet impregnation method, and their NH3-SCR activities were investigated. The Ce/TiO2-SiO2 catalyst with a Ti/Si mass ratio of 3/1 exhibited superior NH3-SCR activity and high N2 selectivity in the temperature range of 250-450 °C. The characterization results revealed that the activity enhancement was correlated with the properties of the support material. Cerium was highly dispersed on the TiO2-SiO2 binary metal oxide support, and the interaction of Ti and Si resulted in greater conversion of Ce4+ to Ce3+ on the surface of the catalyst compared to that on the single metal oxide supports. As a result of in the increased number of acid sites on Ce/TiO2-SiO2 that resulted from the addition of SiO2, the NH3 adsorption capacity was significantly improved. All of these factors played significant roles in the high SCR activity. More importantly, Ce/TiO2-SiO2 exhibited strong resistance to SO2 and H2O poisoning. After the addition of SiO2, the number of Lewis-acid sites was not decreased, but the number of Brønsted-acid sites on the TiO2-SiO2 carrier was increased. The introduction of SiO2 further weakened the alkalinity over the surface of the Ce/TiO2-SiO2 catalyst, which resulted in sulfate not easily accumulating on the surface of the Ce/TiO2-SiO2 catalyst in comparison with Ce/TiO2. [ABSTRACT FROM AUTHOR]

Direct catalytic decomposition of NO has the advantages of being a simple process, producing no secondary pollution, and being good for the economy, which has attracted extensive research in recent years. Perovskite-type mixed oxides, with an ABO3 or A2BO4 structure, are promising materials as catalysts for NO decomposition due to their low cost, high thermal stability, and, of course, their good catalytic performances. In this review, the influence factors, such as A-site substitution, B-site substitution and reaction conditions on the catalytic performance of catalysts have been expounded. The reaction mechanisms of direct NO decomposition are also discussed. Finally, major conclusions are drawn and some research challenges are highlighted. [ABSTRACT FROM AUTHOR]

A bimetallic RhNi/Al 2 O 3 catalyst prepared by galvanic replacement (GR) offers enhanced catalytic CO 2 hydrogenation to selectively produce methane. • Galvanic replacement offers a facile route to bimetallic Rh@Ni core–shell catalysts. • Bimetallic Ni@Rh core–shell catalysts offer significant rate enhancements for CO 2 methanation. • Operando IR identifies reactively-formed CO as the key intermediate to CH 4 production. • Surface formate is a catalytic spectator in methanation. CO 2 utilisation as a chemical feedstock could transform fuels production and help mitigate climate change. Direct CO 2 reduction for energy production requires the development of active, stable, and low-cost catalysts selective for methane. A bimetallic Ni@Rh core–shell catalyst prepared by galvanic replacement (GR) exhibits a 3.5-fold rate enhancement for CO 2 methanation relative to an analogue prepared by chemical reduction (CR) and is twice as active as monometallic Rh/Al 2 O 3. Superior performance of RhNi/Al 2 O 3 (GR) is attributed to Rh dispersion as an atomically thin RhO x shell encapsulating Ni nanoparticles, stabilised by a strong Rh-Ni interaction. Operando IR spectroscopy identifies reactively-formed CO from the dissociative chemisorption of CO 2 over Rh as the key intermediate for methane production. Surface formate from the dissociative chemisorption of CO 2 and subsequent hydrogenation (via spillover from Rh sites) over alumina is a catalytic spectator. This mechanistic insight paves the way to high activity nanostructured catalysts for CO 2 methanation. [ABSTRACT FROM AUTHOR]

The water-gas shift (WGS) reaction has received renewed interest because it is one of the key reactions for producing hydrogen and renewable energy in contemporary technologies like fuel cells and bio-refineries. Catalysts play an important role in WGS reaction for achieving high CO conversion and hydrogen generation activity. Thus, the performance and stability of catalysts are vital for the WGS reaction. In the present work, the CuCe metal-organic framework (MOF) is used as a template to derive the nanostructured Cu/CeO 2 catalyst. The influence of CuCe-MOF templated approach on the WGS activity of Cu/CeO 2 has been established. Different Cu doping levels had a significant impact on WGS activity. Amongst, the Ce 0.8 Cu 0.2 O 2 (Cu2Ce) catalyst had a highest CO conversion (96%). The long-term stability tests further prove that the Cu2Ce catalyst had maintained high CO conversion over 100 h reaction time. XRD and TEM results suggest that different loadings of Cu content have a distinct impact on the dispersion of Cu and the catalytic properties. N 2 O chemisorption results suggest that 20 wt.% of Cu loading resulted in high Cu dispersion (52%) compared to other loadings. The H 2 -temperature programmed reduction (TPR) revealed that the superior catalytic activity of Cu2Ce catalyst could be attributed to the strong reducibility (i.e. lower redox temperature) derived from CuCe-MOF template. It further suggests well-dispersed copper oxide species at low Cu loadings and crystalline copper oxide species at high Cu loadings. This work emphasizes the significance of Cu/CeO 2 catalysts with exceptional catalytic activity and stability for the WGS process with MOF-precursor. [Display omitted] • Cu/CeO 2 catalysts are synthesized using CuCe-BTC-MOF as a porous template. • High Cu dispersion and strong redox behaviour of Cu/CeO 2 are inherited from MOF. • Enhanced CO conversion and a high stability are achieved. • Well-organized MOF-template approach is crucial for improved WGS activity. [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]

Ethanol steam reforming is a promising reaction which produces hydrogen from bio and synthetic ethanol. In this study, the nano-structured Ni-based bimetallic supported catalysts containing Cu, Co and Mg were synthesized through impregnation method and characterized by XRD, BET, SEM, TPR and TPD analysis. The prepared catalysts were tested in steam reforming of ethanol in the S/C = 6, GHSV of 20,000 mL/(g cat h) at the temperature range of 450–600 °C. Among the xNi/CeO 2 (x = 10, 13, 15 wt%) catalyst, the sample containing 13 wt% Ni with surface area of 64 m2/g showed the best performance with 89% ethanol conversion and 71% H 2 selectivity as well as low CO selectivity of 8% at 600 °C and The addition of Cu, Mg, and Co to catalyst structure were evaluated and it was found that the nature of second metal has a strong influence on the catalyst selectivity for H 2 production. Considering to results of TPR analysis, the 13Ni–4Cu/CeO 2 catalyst showed proper reduction which caused in better activity. On the other side based on TPD analysis, the more basic property of 13Ni–4Mg/CeO 2 bimetallic catalyst provided a better condition to methane steam reforming, leading to lower CH 4 selectivity and consequently more H 2 production. The 13Ni–4Cu/CeO 2 exhibited the highest activity and lowest selectivity towards ethanol conversion and CO production about 99% and 4%, while the 13Ni–4Mg/CeO 2 catalyst possessed the highest H 2 selectivity and lowest CH 4 selectivity about 74% and 1% respectively at 600 °C. The Ni–Cu and Ni–Mg bimetallic catalysts shows good stability with time on stream. Image 1 • 13 wt% Ni/CeO 2 catalyst with proper activity and sufficiently hydrogen selectivity at 600 °C. • Increasing the catalytic activity towards ESR reaction by using the promoter of Cu, Mg and Co. • Obtaining almost full conversion over 13Ni–4Cu/CeO 2 catalyst at 600 °C. • Increasing the water-gas shift reaction by using 4 wt% Cu to formulation of 13Ni/CeO 2 catalyst. • High improvement of the methane steam reforming by addition of 4 wt% Mg as promoter. [ABSTRACT FROM AUTHOR]

Abstract The concurrent production of CO x -free hydrogen and multi-walled carbon filaments by thermocatalytic decomposition of methane is advantageous in the environmental and energy catalysis. In the present work, a facile "one-pot" evaporation-induced self-assembly strategy was effectively adopted to fabricate the nickel catalysts supported on mesoporous Al 2 O 3 , SiO 2 , TiO 2 , and MgO, and their catalytic activities for methane decomposition were evaluated for the first time. The structural, textural, and redox properties of the as-obtained materials were characterized using a number of analytical techniques. The nitrogen sorption analysis indicated the presence of a mesoporous structure due to homogeneous aggregation of the catalyst particles with a high specific surface area of 32–236 m2/g. Among all of the catalysts, Ni/MgO exhibited the best catalytic activity for methane decomposition (65% methane conversion at 600 °C and GHSV of 48,000 mL/(g h)). The activity increased when Ni loading increased from 25 to 55 wt%. The investigation on the correlation between catalytic performance and promoter doping effect suggests that incorporating copper into the MgO support considerably enhanced the catalytic activity and stability at high temperatures. The XPS results reveal that doping of Cu to Ni/MgO enhanced the adsorption and activation of oxygen molecules. In addition, the disordered crystalline carbon filaments with different diameters and good crystallinity were generated on the surface of the Cu-doped Ni/MgO catalysts. Graphical abstract Unlabelled Image Highlights • The work is focused on pure hydrogen production via catalytic CH 4 decomposition. • One-pot synthesis allows to prepare Ni catalysts supported on various metal oxide. • The catalysts were characterized for their physicochemical properties and activity. • The Ni supported on MgO shows a higher activity than that supported on other metal oxides. • Effect of Ni content and Cu addition in Ni/MgO were investigated in detail. [ABSTRACT FROM AUTHOR]

Abstract Nanocrystalline Ni/CeO 2 catalysts with various loadings of Ni (10, 15, 20, and 25%) were synthesised by a facile solvent deficient precipitation method for methane autothermal reforming process. The characterisation techniques such as XRD, BET, TPH, H 2 -TPR were carried out on fresh and spent samples to investigate the catalytic properties of the Ni/CeO 2. On the basis of characterisation results, the 20% Ni/CeO 2 performs the best activity among the catalysts with different Ni contents. The optimal reaction conditions for autothermal methane reforming has been investigated by evaluating the effect of reaction parameters including the reactivity temperature, the gas hourly space velocity (GHSV) and H 2 O/CH 4 (S/C) and O 2 /CH 4 (O/C) molar ratios. The stability of 20 wt% Ni/CeO 2 catalyst at 700 °C is examined for 20 h on-stream reaction. It reveals that the methane conversion starts a graduate decrease trend from the second 10 h, which is found to be because of the sintering of Ni nanoparticles by TPH and BET analysis. Graphical abstract Image 1 Highlights • Nanocrystalline Ni/CeO 2 catalysts were studied for autothermal reforming reaction. • 20 wt% Ni/CeO 2 with the large surface area and good reducibility exhibited the highest catalytic performance. • 20 wt% Ni/CeO 2 shown excellent thermal stability at 700 °C for 20 h on-stream reaction. • Carbon depositions were determined to occur on the surface of the samples with high Ni loading. [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]