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China implemented the China VI emission standard in 2020. The China VI emission standard has added requirements for the RDE (real-world driving emission) test. To evaluate vehicle CO2 emission for different vehicles, 10 conventional gasoline vehicles were tested under the RDE procedure using the PEMS (portable emission testing system) method. All vehicles tested meet the sixth emission regulation with a displacement of 1.4 L~2.0 L. Among the vehicles tested, the highest CO2 emission factor was 281 g/km and the lowest was 189 g/km, while the acceleration of RDE gets a wider distribution, varying from −2.5 m/s2 to 2.5 m/s2. The instantaneous mass emission rate could reach around 16 g/s. The amounts of total CO2 emission in the positive region and the negative region make up 82~89% and 11~18% of the overall CO2 emission during the entire RDE driving period, respectively. The same vehicle has a wide range of CO2 emission factors at different VSP (vehicle specific power) intervals. Different RDE test conditions can lead to large differences in CO2 emissions. [ABSTRACT FROM AUTHOR]

Route topography is an important test boundary of real driving emission (RDE) tests. However, the RDE test boundaries, such as atmospheric environment, driver behavior, route topography, and traffic congestion, are random, uncertain, and completely coupled. It is difficult to know to what extent route topography can determine on-road emissions, especially in a region with hilly topography. In this regard, the neural network predictor importance algorithms were proposed to measure the importance of the route topography test boundary. Based on tens of thousands of data window samples from the RDE tests in Chongqing, factor analysis was performed to reduce the data dimensionality and eliminate information overlap, and neural network models were established to predict pollutant emissions and calculate the relative importance of input variables. The results show that route topography is comparable to trip dynamics for on-road emissions but the importance of the route topography test boundary is not fully appreciated in the existing RDE regulation, making mountain cities suffer from severe vehicle emissions that are not effectively controlled. • Route topography impact on vehicle emissions was explored by neural network models. • Predictor importance algorithms using sensitivity analysis were introduced. • Data dimensions were downsized to eliminate the overlap of trip dynamic variables. • Data windows were treated as trip sections to expand the sample space significantly. • Route topography test boundary requires revision in the RDE test regulation. [ABSTRACT FROM AUTHOR]

Copper-catalyzed of 2-iodoanilines, benzylamines, and sulfur powder are reported to afford benzothiazoles in a simple by using water as solvent. A variety of 2-arylbenzothiazoles were obtained in moderate to good yields up to 88%. [ABSTRACT FROM AUTHOR]

Three-component reactions involving amines, aldehydes, and elemental sulfur powder are reported to afford thioamides in a simple one-pot procedure in the absence of a catalyst. A variety of thioamides can be obtained in good to excellent yields up to 88 %. [ABSTRACT FROM AUTHOR]

Surface property modification of catalyst support is a straightforward approach to optimize the performance of supported noble metal catalysts. In particular, oxygen vacancies and hydroxyl groups play significant roles in promoting noble metal dispersion on catalysts as well as catalytic stability. In this study, we developed a nanoflower-like TiO2-supported Pd catalyst that has a higher concentration of oxygen vacancies and surface hydroxyl groups compared to that of commercial anatase and P25 support. Notably, due to the distinctive structure of the nanoflower-like TiO2, our catalyst exhibited improved dispersion and stabilization of Pd species and the formation of abundant reactive oxygen species, thereby facilitating the activation of CO and O2 molecules. As a result, the catalyst showed remarkable efficiency in catalyzing the low-temperature CO oxidation reaction with a complete CO conversion at 80 °C and stability for over 100 h. [ABSTRACT FROM AUTHOR]

Abstract: Al- and Zn-containing mesoporous molecular sieves (SBA-15) were prepared by an impregnation method and were used as catalysts for the catalytic dehydrogenation and cracking of industrial dipentene, an important natural feedstock. The catalysts were characterized by X-Ray fluorescence spectroscopy (XRF), X-Ray diffraction (XRD), N2 adsorption/desorption, transmission electron microscopy (TEM), magic angle spinning nuclear magnetic resonance (27Al MAS NMR) and Fourier transform infrared spectroscopy (FT-IR) techniques. The characterization results suggest that the active components were introduced without changing the mesostructure of SBA-15. FT-IR revealed that Al/SBA-15 shows weak Brönsted acidity and strong Lewis acidity, while Zn/SBA-15 only possesses moderate Lewis acidity. Dehydrogenation and cracking products, such as toluene, were found in the dipentene conversion over Al/SBA-15, while for Zn/SBA-15, p-cymene was the major dehydrogenation product. Along with the strong Brönsted acidity and high cracking activity of HZSM-5, our results suggest that the reaction pathway is determined by the acidic sites. Stability tests showed the deactivation is also related to the acidity. The highest yield of p-cymene reaches to 86.7% on Zn/SBA-15 at 723K. [Copyright &y& Elsevier]

Nitrous oxide (N2O) is a greenhouse gas and damages the ozone layer. Nitrous oxide from nitric acid plants is currently the major industrial N2O source. Many catalysts are active for pure N2O decomposition, but few are effective under realistic conditions, due to the relatively low N2O concentration compared to those of inhibitors present in the exhaust gases, i.e. H2O, O2 and NOx. In the present work, Si-SBA-15 and Al-SBA-15 were used to prepare Fe, Ru or Rh catalysts by ion-exchange, impregnation or precipitation method. The effect of steam treatment was also studied. Their activities were evaluated in an automated six-flow reactor system using a model tail-gas under conditions representative for nitric acid plants.The performance depends on the metal species and preparation method. When the carrier, preparation method and metal loading are the same, the activity decreases as follows: Rh > Ru > Fe. Steam-treatment has little influence on catalytic activity unlike for FeZSM-5 catalysts. Impregnated Rh on Al-grafted SBA-15 catalyst shows the best performance per weight of catalyst. However, per mol of active metal (Rh, Ru and Fe) species, catalysts by ion exchange are better than those by impregnation. It is concluded that the improved performance of Rh on Al-grafted SBA-15 is caused by a better dispersion and an enhanced stability due to Al incorporation, but not due to an enhanced acidity thereof. [Copyright &y& Elsevier]

Mn–Al and Mg–Mn–Al hydrotalcite-like compounds (HTlcs) were synthesized by a coprecipitation method. The activity of the calcined HTlcs for hydrogenation of methyl benzoate to benzaldehyde was tested. The effects of Mn/Al and Mg/Mn ratio, preparation and reaction conditions, and potassium promoter on the catalytic performance of the catalysts were investigated. The prepared catalysts give better performance than conventional 10% Mn/γ-Al2O3 catalyst. The conversion of methyl benzoate and selectivity to benzaldehyde on 3% K/Mg0.2Mn1.8Al1 catalyst at 390 °C are 90.0 and 88.0%, respectively. XRD, TPR and CO2-TPD studies show that the redox and basic properties of the catalysts play important roles in the reaction. A suitable degree of reduction and a small number of basic sites on the catalyst lead to a high activity and selectivity to benzaldehyde. [Copyright &y& Elsevier]

Compressed natural gas (CNG) taxis represent the most ubiquitous and dynamically active passenger vehicles in urban settings. The pollutant emission characteristics of in-use CNG taxis driving on a typical mountain city before and after three-way catalyst (TWC) replacement was examined using a modular on-board portable emissions measurement system (PEMS), the OBS-ONE developed by Horiba. The results showed that the exhaust NO of CNG taxis equipped with deactivation TWC exceeded the emission limits, even higher than gasoline vehicles. The high emission rate of CNG taxis is mainly concentrated on road slopes between a 2% and 6% gradient and a deceleration rate in the interval of [0.5, 4], respectively, which results in higher emissions from CNG taxis traveling in the mountain city of Chongqing than other cities and vehicles. Moreover, the pollutant emission rates of the in-use CNG taxis were highly correlated with the velocity and the vehicle specific power (VSP). After a new TWC replacement, the emission factors of carbon monoxide (CO), total hydrocarbons (THC), nitrogen oxides (NOx), and particle number (PN) decreased by 85.21–89.11%, 68.71–85.49%, 60.91–81.11%, and 62.26–68.39%, respectively. Our results will provide guidance for urban environments to carry out the comprehensive management of in-use vehicles and emphasize the importance of TWC replacement for CNG taxis. [ABSTRACT FROM AUTHOR]

Surface coating technology is an effective anti-corrosion strategy which can form a layer of anti-corrosion film on metal surface, effectively preventing it from oxidation and corrosion. Among various strategies, silanization treatment of metals is the most commonly used one. However, using silane-based coatings alone often leads to poor anti-corrosion performance due to insufficient mechanical strength and presence of surface defects. In order to improve the corrosion resistance of silane coatings, a hybrid surface coating has been constructed by introducing epoxy resin and Ag/TiO 2 nanoparticles into the silane film in this work. After adding epoxy resin, the thickness of the silane film greatly increases, which improves its mechanical properties. Ag/TiO 2 nanoparticles can enhance the cross-linking between silane molecules and epoxy resin, thereby preventing formation of surface defects. The epoxy resin-silane-Ag/TiO 2 composite surface coating is coated on the surface of AA2024 aluminum alloy using spin coating method. Electrochemical and salt spray tests indicate excellent corrosion resistance performance of the composite coating. This composite coating technology may have potential applications on the surfaces of various metal products such as medical devices and aerospace materials, and will shed light on the development of new surface coating technologies. [Display omitted] • Hybrid coating composed of silane, epoxy resin and Ag/TiO 2 with excellent anti-corrosion performance was designed. • Dense internal cross-linking and few defects of the hybrid coating improve the property of the silane film. • The hybrid coating has good photocatalytic performance for self-cleaning. [ABSTRACT FROM AUTHOR]

Chemical equations for the article "Synthesis of 2-Arylbenzothiazoles by Copper-Catalyzed One-Pot Three-Component Reactions in Water" by H. Xu, appeared in the periodical "Journal of Heterocyclic Chemistry" is presented.

A three-component reaction of aldehydes, amines, and elemental sulfur is developed to give good yields of N-monosubstituted thiobenzamides. [ABSTRACT FROM AUTHOR]

Coalbed methane is a significant source of methane in the atmosphere, which is a potent greenhouse gas with a considerable contribution to global warming, thus it is of great importance to remove methane in coalbed gas before the emission. Exploring the economical non-noble metal catalysts for catalytic methane combustion (CMC) has been a wide concern to mitigate the greenhouse effect caused by the emitted low-concentration methane. Herein, a series of Mn-doped Co3O4 catalysts have been synthesized by the environmentally friendly solid-state method. As a result, the Mn0.05Co1 catalyst performed the best CMC activity (T90 = 370 °C) and good moisture tolerance (3 vol% steam). The introduction of an appropriate amount of manganese conduced Co3O4 lattice distortion and transformed Co3+ to Co2+, thus producing more active oxygen vacancies. Mn0.05Co1 exhibited better reducibility and oxygen mobility. In situ studies revealed that methane was adsorbed and oxidized much easier on Mn0.05Co1, which is the crucial reason for its superior catalytic performance. [ABSTRACT FROM AUTHOR]

With the development of internet of things and artificial intelligence electronics, metal oxide semiconductor (MOS)‐based sensing materials have attracted increasing attention from both fundamental research and practical applications. MOS materials possess intrinsic physicochemical properties, tunable compositions, and electronic structure, and are particularly suitable for integration and miniaturization in developing chemiresistive gas sensors. During sensing processes, the dynamic gas–solid interface interactions play crucial roles in improving sensors' performance, and most studies emphasize the gas–MOS chemical reactions. Herein, from a new view angle focusing more on physical gas–solid interactions during gas sensing, basic theory overview and latest progress for the dynamic process of gas molecules including adsorption, desorption, and diffusion, are systematically summarized and elucidated. The unique electronic sensing mechanisms are also discussed from various aspects including molecular interaction models, gas diffusion mechanism, and interfacial reaction behaviors, where structure–activity relationship and diffusion behavior are overviewed in detail. Especially, the surface adsorption–desorption dynamics are discussed and evaluated, and their potential effects on sensing performance are elucidated from the gas–solid interfacial regulation perspective. Finally, the prospect for further research directions in improving gas dynamic processes in MOS gas sensors is discussed, aiming to supplement the approaches for the development of high‐performance MOS gas sensors. [ABSTRACT FROM AUTHOR]

Zeolitic imidazolate framework-8 (ZIF-8) nanozymes were successfully synthesized by using non-ionic surfactant Triton X-100 as regulator. The surfactant molecules can bind on ZIF-8 surface to modulate the nucleation and facet growth, which therefore produces ZIF-8 crystals with controlled morphology and size. The as-prepared ZIF-8 crystals reproduce the functional property of natural carbonic anhydrase (CA) by showing excellent CA-like esterase activity. The catalytic activity of ZIF-8 nanozymes was greatly enhanced at high temperature, which is superior to natural CA and is of great potential for practical applications. Moreover, the esterase activity of ZIF-8 shows great dependence on the crystal size. Basically, smaller ZIF-8 nanozymes had higher catalytic activity at a specified temperature, except for the smallest ZIF-8 crystals with size of ~50 nm that gave reduced activity due to aggregation at high temperatures of 60 or 80 °C. In addition, colorimetric experiments showed that ZIF-8 nanozymes showed similar hydration activity to that of natural CA. The study probes into the effect of nonionic surfactant on ZIF-8 synthesis as well as the abnormal size effect at higher temperature, which is of great help for the development of suitable nano-enzymes for industry applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Controlled fabrication of uniform graphene oxide (GO) films is of great demand for many applications such as biomedical and biosensing materials. Surface-supported GO films with different surface coverage and density have been successfully fabricated by Langmuir–Blodgett (LB) method. The dialyzed GO sheets with sizes of smaller than 200 nm are used for LB assembly so as to achieve well control over the quality of the GO films. The dialysis procedure can remove soluble impurities from the GO sheets to adjust the surface composition and physicochemical properties. GO sheets within nanometer sizes can avoid edge folding and stacking during LB assembly and get better control of interactions between GO sheets. These aspects help to fabricate the uniform LB assemblies of GO sheets successfully, which can then be transferred onto the solid surface to give GO films with controlled surface coverage and density. The surface-supported GO films show high stability and biocompatibility, which can mediate cell growth and proliferation. The study not only provides ways for controlling the physicochemical properties of the GO sheets but also depicts the controlled fabrication of uniform GO films for specific applications. [ABSTRACT FROM AUTHOR]

Ni–Zr/SiO 2 catalyst was prepared using the impregnation method and was employed for the dry reforming of methane. The Ni species ensured a superior dispersion of the Zr species, promoting the formation of low temperature active center for the target reaction, while the introduction of promoter Zr changed the nature of the active center. At high temperature, the Ea values corresponding to CH 4 and CO 2 on Ni–Zr/SiO 2 catalyst were much lower than those on Ni/SiO 2 catalyst. In addition to facilitate the activation of the C–H bond in CH 4 , the Zr promoter on Ni–Zr/SiO 2 catalyst also facilitated the formation of CO ads and O ads species at low temperatures, and accelerated the formation–decomposition of intermediate formates. These factors including the synergetic effect of Ni and Zr species led to the enhancement of the activation of both CH 4 and CO 2 at low temperatures, with 2.0% initial conversion of both CH 4 and CO 2 (at 1 h) achieved at 400 °C. [ABSTRACT FROM AUTHOR]

Direct conversion of syngas to aromatics over metal oxide‐zeolite (OX‐ZEO) composite catalysts is a novel route for efficient utilization of carbon resources. To realize a high activity with considerable selectivity to aromatics and stability, the design of synergetic OX‐ZEO catalyst to meet complex kinetics still remains a great challenge. In this work, a synergetic dual‐oxide/zeolite catalyst was developed to tune the coupling between CO and H2 activation through active H species migration, by adopting ZnZrOx oxide with stable single‐layer Zn−O structure for H2 activation and CeZrOx oxide with abundant oxygen vacancies as the CO activation component. The ratio and the proximity of CeZrOx and ZnZrOx is essential for the catalyst activity and stability. The optimal catalyst 1CeZrOx‐2ZnZrOx/Z5@Si shows a superior catalytic performance with 75.6 % aromatics selectivity at a CO conversion as high as 57.5 %. After induction period, the catalyst exhibits excellent stability for 1100 h, keeping the high selectivity above 75 % with an average conversion of 43 %. This work will provide a new perspective to design a high performance and long‐life OX‐ZEO composite catalyst for direct conversion of syngas to high value chemicals. [ABSTRACT FROM AUTHOR]

The acidity and Ga-species status in the zeolite play a crucial role in the CO 2 -assisted propane dehydroaromatization (CO 2 -PDA). In this work, a copper modified Ga-MFI zeolite (Cu/Ga-MFI) with well dispersed framework Ga species was fabricated. A remarkable aromatics selectivity of 73% at propane conversion of 93.6% was achieved on Cu/Ga-MFI catalyst. The Ga atoms in MFI framework can create a moderate acid strength, while the introduced Cu provide an appropriate Brønsted/Lewis acid distribution, enhancing the synergy between metal-related species and the zeolite. Besides, DFT results indicate that the acid sites in Ga-MFI are more preferable for the dehydrogenation of propane instead of the C-C cleavage. Moreover, CO 2 can inhibit coke formation through reverse Boudouard and reverse water gas shift reaction, which endows Cu/Ga-MFI catalyst with superior anti-coking ability and regeneration stability. This work provides a novel approach for designing catalysts with high activity, aromatics selectivity, and stability for CO 2 -PDA reactions. [Display omitted] • H-type Al-free Ga-MFI with Ga located in frameworks is successfully fabricated. • Cu/Ga-MFI shows a superior aromatics selectivity and stability in CO 2 -PDA reaction. • The moderate acid strength from Ga in MFI is favored by propane dehydrogenation. • The synergy between Brønsted/Lewis acid is crucial for catalytic performance. • The introduction of Cu promotes CO 2 activation and inhibits the carbon deposition. [ABSTRACT FROM AUTHOR]

The bisthienylethene (BTE) class is one of the most intensely studied type of photochromatic dye which attract great attention from researchers seeking to exploit light responsive switches in an extensive diversity of fields. BTE is the subject of many avenues of research. We report here the synthesis of a new diarylethene‐porphyrin photoswitchable copolymer via the electropolymerization of zinc octaethyl porphyrin and pyridine substituted diarylethene. The electropolymerization was monitored by electrochemical quartz crystal microbalance (EQCM). The copolymer was characterized by electrochemistry, UV‐Vis spectroscopy, X‐ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). The incorporated diarylethene maintains its reversible photochromism upon the UV‐Vis radiation with multiple cycles of ring‐opening and closing. Attention is focused on the ways the polymer environment affects BTE photochromism. [ABSTRACT FROM AUTHOR]

Abstract: Hydrophobicity modification of the intrinsic polarity of the surface of SBA-15 mesoporous by ethoxytrimethylsilane was used in this work to make hybrid organic–inorganic mesoporous matrix. This matrix was functionalized with perfluorosulfonic acidic Nafion resin by a post-synthetic impregnation method. Characterized by N2-physisorption, XRD, and transmission electron micrographs (TEM), all the materials synthesized were highly ordered. Elemental analysis, 29Si MAS NMR, thermal gravimetric analysis (TGA), energy-dispersive X-ray (EDX) and potentiometric titration showed that trimethylsilane is grafted on the surface by capping the OHs and the Nafion resin was incorporated, revealing a strong solid acid with hydrophobic surface. The alkylation of isobutane/1-butene was thereafter evaluated on each material under specified conditions. Compared with the polar surface of conventional SBA-15 and commercial Nafion silica nanocomposite SAC-13, methyl-modified surface of SBA-15 material (denoted as Me-SBA-15) is a much better solid acid catalyst for isobutane/1-butene alkylation. [Copyright &y& Elsevier]

Abstract: Dehydrogenation of ethane to ethylene in the presence of carbon dioxide was investigated over various gallium-based catalysts. Ga2O3/HZSM-5 catalysts show better stability than β-Ga2O3, and the higher Si/Al ratio HZSM-5 supported gallium oxide catalysts are more resistant to deactivation. The Ga2O3/HZSM-5(97) catalyst exhibits both high activity and stability for dehydrogenation of ethane, with an ethane conversion of 15% and ethylene selectivity of 94% without any observable trend of deactivation in 70h. The results of NH3-TPD and FT-IR spectra of adsorbed pyridine revealed that the enhancement of the catalyst stability with increasing Si/Al ratio of the support is caused by the decrease of the acidity of the catalysts, resulting in the suppression of the side reactions, such as cracking and oligomerization. The promoting effect of CO2 on the dehydrogenation reaction is attributed to the reverse water gas shift reaction. The catalyst stability is also enhanced by the introduction of CO2. [Copyright &y& Elsevier]

Abstract: Series of Rh/SBA-15 catalysts were prepared by impregnation and grafting method applying different Rh precursors. The catalytic behaviors of N2O decomposition over these catalysts were tested in an automated eight flow reactor system. The catalysts were characterized by X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), N2 adsorption/desorption, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. The results showed that the dispersion of Rh species on the catalysts is closely related to the molecular size and the hydrophobic property of the precursors comparing to the hydrophilic support, better dispersion results were found in catalysts by impregnation of smaller precursors, while by grafting better dispersion resulted from big precursor. On the other hand, the activities of the catalysts match well with the Rh dispersion status. Rh/SBA-15-CDCR starting from [(CO)2RhCl]2 showed good dispersion and gave the best N2O decomposition activity. [Copyright &y& Elsevier]

Improving catalytic selectivity with high conversion meets big challenge for direct conversion of syngas (CO/H2) to aromatics (STA). Here, a series of LaBO3 (B=Fe, Co, Ni, Mn, Cr) perovskite oxides was synthesized and applied as metal oxide component of OX‐ZEO bifunctional catalysts for STA firstly. By combining with HZSM‐5, LaFeO3, LaMnO3 and LaCrO3 exhibited good performance on syngas conversion. For the bifunctional catalyst of LaFeO3/HZSM‐5, a superior catalytic performance with 82.0 % selectivity to aromatics at 28.5 % CO conversion was achieved. The composition of B‐site metals in perovskites and its stabilization in the structure are essential for activity of STA reaction. In situ DRIFTs study revealed the syngas conversion over perovskite followed the surface formate and methoxy intermediate species transformation pathway. [ABSTRACT FROM AUTHOR]

A new metal–organic framework (MOF) with both coordination linkages and covalent linkages is prepared by coordinating CuI with pyrazolate for an aldehyde‐functionalized trinuclear complex, and subsequent imine condensation with p‐phenylenediamine, a reaction typical for covalent organic framework (COF) synthesis. This MOF×COF collaboration yields FDM‐71 with honeycomb layers stacked in eclipsed fashion. After dissociating the CuI‐pyrazolate coordination in FDM‐71, the obtained organic components carry the information of structural defects, and thus vacancy identity (aldehyde‐based unit vacancy and amine‐based unit vacancy) and concentration are definitely resolved. Further to the redox catalytic activity inherited from the complex, FDM‐71 features effective photosensitizing activity. The two functions integrated in one well‐defined structure is demonstrated by its high efficiency in decomposing H2O2 and consequent excitation of O2 to reactive oxygen species. [ABSTRACT FROM AUTHOR]

A new metal–organic framework (MOF) with both coordination linkages and covalent linkages is prepared by coordinating CuI with pyrazolate for an aldehyde‐functionalized trinuclear complex, and subsequent imine condensation with p‐phenylenediamine, a reaction typical for covalent organic framework (COF) synthesis. This MOF×COF collaboration yields FDM‐71 with honeycomb layers stacked in eclipsed fashion. After dissociating the CuI‐pyrazolate coordination in FDM‐71, the obtained organic components carry the information of structural defects, and thus vacancy identity (aldehyde‐based unit vacancy and amine‐based unit vacancy) and concentration are definitely resolved. Further to the redox catalytic activity inherited from the complex, FDM‐71 features effective photosensitizing activity. The two functions integrated in one well‐defined structure is demonstrated by its high efficiency in decomposing H2O2 and consequent excitation of O2 to reactive oxygen species. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mn 1 Ni x O y oxides catalyst with controlled Ni content were prepared. • The strength of Mn O bond was weakened and the catalytic activity was enhanced. • Monolithic-scale catalyst shown 45 days stability with good thermal shock resistance. • The structure–activity relationship and reaction mechanism were verified. Developing highly active and thermally stable transition-metal-oxide catalysts for light alkane catalytic oxidation is of great importance but very challenging. In the work, the catalytic performance for propane deep oxidation was significantly enhanced on the Mn 1 Ni x O y solid solution catalyst by weakening the Mn–O bond strength of manganese oxide. The characterization results combined with DFT calculations demonstrated that the introduction of Ni could create additional defect sites, resulting in a significant improvement of the adsorption and the activation of both propane and oxygen molecules. The optimal Mn 1 Ni 0.15 O y catalyst exhibits abundant oxygen vacancies with low Mn O bond strength, high redox ability and oxygen mobility, which account for its superior activity. Specifically, the specific reaction rate on Mn 1 Ni 0.15 O y is three times higher than that on pure Mn 2 O 3. Moreover, a Mn 1 Ni 0.15 O y /cordierite monolithic catalyst was made by wash-coating method, and exhibited remarkable catalytic performance and stability on catalytic oxidation of propane during the 45 days (1080 h) on stream, even after tens of high temperature thermal shocks (up to 650 ℃), which declared to be satisfied for practical industrial applications. This work will shed light on designing high-efficiency and long-life environmental catalyst for VOCs elimination. [ABSTRACT FROM AUTHOR]

Thermo-catalytic CO 2 hydrogenation with renewable energy has become one of the promising alternatives to fossil carbon-based routes for the production of bulk chemicals and has been extensively researched in recent years. And the heterogeneous oxide–zeolite (OX–ZEO) bifunctional catalysts have received much attention due to their high product selectivity. However, the need for multifunctional active sites, the complexity of tandem cascade reactions and the difficulty in understanding reaction mechanisms pose significant challenges for the design of effective catalysts. In this review, we present an overview of recent advances in the catalytic hydrogenation of CO 2 to value-added products over OX–ZEO bifunctional catalysts, with particular emphasis on the role of the oxide. The nature of the metal oxide, the modification of oxides to improve catalytic performance in CO 2 hydrogenation and the reaction mechanisms are discussed. Finally, the current challenges and future perspectives of the catalytic conversion of CO 2 to hydrocarbons are briefly presented. [Display omitted] • Metal oxides in OX-ZEO bifunctional catalysts for direct hydrogenation of CO 2 are briefly summarized. • Enhancement of OX/ZEO catalytic performance in CO 2 hydrogenation as well as the mechanisms are discussed. • Challenges for OX-ZEO catalysts in hydrogenation of CO 2 into value-added chemicals are addressed. [ABSTRACT FROM AUTHOR]

A series of mesoporous silica (KIT-6, MCM-41 and SBA-15) supported Pd catalysts were successfully synthesized and applied for selective oxidation of glyoxal. All of these catalysts exhibited significantly higher activity than commercial Pd/C. Among them, Pd/KIT-6 exhibited the best activity and selectivity with 41.3% glyoxal conversion and 57.0% selectivity to glyoxalic acid. The better performance of Pd/KIT-6 was attributed to its three-dimensional mesoporous structure. The three-dimensional mesoporous structure of KIT-6 could enhance Pd dispersion, providing sufficient accessible active sites which improved the conversion of glyoxal. Meanwhile, the better mass transfer capability of Pd/KIT-6 allowed glyoxalic acid to leave the catalyst easily, reducing the probability of over-oxidation. The ratio of kI (rate constant of initial oxidation reaction) to kII (rate constant of over-oxidation) was compared among three catalysts. The kI/kII of Pd/KIT-6 (0.50) was higher than that of Pd/MCM-41 (0.39) and Pd/SBA-15 (0.34), which reflected its best selectivity from kinetic aspect. [ABSTRACT FROM AUTHOR]

• Honeycomb-structured graphene (HSG) was used to support the K-MgFe catalysts. • Unprecedentedly high activity and productivity of lower olefins were obtained in FTO. • The synergetic effect of Mg and K enhanced the adsorption and dissociation of CO. • The catalyst also showed better durability than typical FTO catalysts. • HSG enabled fast heat dissipation and confined the sintering of the active phase. Three-dimensional (3D) honeycomb-like structured graphene (HSG)-supported ternary K-promoted magnesium ferrite catalysts (K-MgFe/HSG) are prepared and evaluated in Fischer–Tropsch synthesis to the lower olefins (FTO). The catalysts bear interconnected mesoporous-macroporous framework of graphene nanosheets decorated with homogeneously sized magnesium ferrite nanoparticles (NPs). Under typical FTO reaction conditions, the composition-optimized 1K-MgFe/HSG catalyst affords a reduced CO 2 selectivity of 40.4%, an excellent weight specific activity to hydrocarbons of 1825 μmol CO g Fe −1 s−1, and an appreciable selectivity to the lower olefins (C 2 C 4 olefins) of 57.8%, thus giving rise to a record high productivity of the lower olefins of 1055 μmol CO g Fe −1 s−1. The excellent catalytic efficiency is tentatively attributed to the synergetic effect of Mg and K on adsorption and dissociation of CO. The catalyst also exhibits better durability than previously reported iron-based FTO catalysts, without significant changes in the catalytic performance and the size of the iron carbide NPs after 120 h on stream, highlighting the crucial role of the 3D porous HSG support in restricting the agglomeration of the active phase during the challenging high-temperature and exothermic FTO reaction. [ABSTRACT FROM AUTHOR]

Ceria‐zirconia solid solutions with tunable surface oxygen vacancy have been used in the direct conversion of syngas into aromatics after coupling with ZSM‐5 zeolite. A high selectivity of 83.1 % to aromatics has been achieved from syngas with low H2/CO ratio over Ce0.2Zr0.8O2/ZSM‐5 bifunctional catalyst. The surface oxygen vacancy of Ce0.2Zr0.8O2 is supposed to facilitate the formation of oxygenates which act as intermediates for C−C coupling and aromatization on ZSM‐5, and thus contribute to the well kinetic matching between C−O activation and C−C coupling over these two components of catalyst. The ceria‐zirconia with abundant surface oxygen vacancies and enhanced lattice oxygen mobility intimately mixed with ZSM‐5 zeolite with moderate acidity and crystal size play an important role in the catalytic performance. O‐pen vacancy: By tuning the surface oxygen vacancy of ceria‐zirconia solid solutions, a well kinetic matching between C−O activation and C−C coupling can be achieved, and syngas with low H2/CO ratio is directly converted into aromatics with a high selectivity over a ceria‐zirconia/HZSM‐5 bifunctional catalyst. [ABSTRACT FROM AUTHOR]

A novel material of hollow porous NiO@CeO 2 octahedron (HPOC) derived-from cerium-based metal-organic frameworks (MOF) was prepared as a high-performance catalyst for N 2 O decomposition. Octahedron-shaped cerium-based MOF was successfully synthesized with formic acid as a structure-modulating agent by rational controlling the volume ratio of N,N-dimethylformamide and formic acid at 4:1. The obtained NiO@CeO 2 -HPOC was systematically characterized to reveal its morphology, structure and surface properties. TEM, SEM and N 2 adsorption-desorption isotherms results confirm the well-defined octahedral morphology and hollow porous structures of NiO@CeO 2 -HPOC. EDS mapping and XRD studies indicate that NiO@CeO 2 -HPOC hybrid composite exhibits relatively homogeneous Ni dispersion and small NiO size, which comes from the unique coordination bond and porosity of cerium-based MOF precursor. H 2 -TPR analysis shows that uniform nickel distribution enables the highly dispersed NiO species in NiO@CeO 2 -HPOC. Furthermore, Raman and XPS results indicate that NiO@CeO 2 -HPOC possesses large amount of oxygen vacancies. The hollow porous structures, homogeneous Ni dispersion, as well as large amount of oxygen vacancies facilitate the catalytic efficiency. As a result, NiO@CeO 2 -HPOC exhibits a high catalytic activity and enhanced O 2 tolerance for N 2 O decomposition. [ABSTRACT FROM AUTHOR]

A series of ZSM-5 zeolites with tunable mesoporosity were synthesized by a facile ultrasound-assisted method. XRD, FT-IR and NH 3 -TPD results exhibited that as-synthesized ZSM-5 kept the MFI structure as well as the original acidity. Traced by TEM techniques, the crystallization process, especially the state of initial amorphous gel, was found notably affected by the ultrasound treatment by breaking the weak bonds, which led to formation of mesopores in crystals. The ZSM-5 catalysts with abundant mesoprores inhibited coking significantly and showed high catalytic stability for methanol to propylene reaction. The Z5-us-60 catalyst exhibited the highest catalytic stability for >600 h at a high WHSV of 4.0 h −1 . [ABSTRACT FROM AUTHOR]

Supported platinum catalysts are widely used in the catalytic combustion of volatile organic compounds due to their excellent catalytic activity, but SO 2 poisoning is one of the critical problems for the industrial application. In this work, a series of sulfated ceria-zirconia composite oxides (CeZrO x) supported platinum catalysts (Pt/CeZr-S) were prepared through the support sulfation strategy. In the catalytic combustion of toluene, the Pt/CeZr-S catalyst with 0.5 wt% Pt and 15 wt% sulfuric acid loading amounts exhibited the significantly increased activity compared with the reference Pt/CeZr catalyst. Moreover, the tolerance to SO 2 poisoning of Pt/CeZr-S catalyst was greatly improved in the presence of 50 ppm SO 2. Various characterization methods including XPS, NH 3 -TPD and in-situ DRIFTS were performed to reveal the structure-activity relationship and SO 2 tolerance mechanism. The higher concentration of metallic Pt0 species resulting from the interaction of Pt species and acidic CeZr-S support contributed to the enhanced catalytic activity. Meanwhile, the increased acidity strength and total acidity amounts over Pt/CeZr-S catalysts could affect the sulfation process, resulting in significant inhibition of the adsorption and further accumulation of sulfur species. [Display omitted] • Sulfated Pt/CeZr catalysts were developed through the support sulfation. • Superior activity and SO 2 tolerance were achieved for catalytic combustion of toluene. • The higher metallic Pt0 concentration led to enhanced catalytic activity. • Enhanced surface acidity was responsible for the superior SO 2 tolerance. • The SO 2 tolerance mechanism was elucidated. [ABSTRACT FROM AUTHOR]

Poly-zinc-octaethylporphyrin/P 5 W 30 films have been obtained through incorporation of Preyssler-type polyoxometalate ions, namely [NaP 5 W 30 O 110 ] 14- ( P 5 W 30 ) into zinc octaethylporphyrin/viologen-based polymers ( poly-ZnOEP ) films. The latter has been achieved through a metathesis reaction involving exchange of the initial counter ions (PF 6 − ) of the positively charged poly-ZnOEP by P 5 W 30 . The investigated polymers involve ZnOEP units covalently linked either through a dicationic mono-viologen or through a tetracationic bis-viologen spacer. These copolymers have been characterized by UV/Vis absorption spectroscopy, X-ray photoelectron spectroscopy, electrochemistry, AFM and by electrochemical impedance spectroscopy. Formation of the polymers through electropolymerization of viologen and porphyrin building blocks has also been monitored by EQCM. QCM measurements have been carried out to study the exchange of PF 6 − by [NaP 5 W 30 O 110 ] 14− . Finally, the photovoltaic performances of these polymers have been assessed by photocurrent transient measurements carried out under visible illumination. [ABSTRACT FROM AUTHOR]

Abstract: The dehydration of glycerol into acrolein was investigated over small‐sized γ‐Al2O3 prepared by a metal–organic framework (MOF) templated method. The particle size of alumina strongly affected the final physicochemical properties of γ‐Al2O3 as well as its catalytic activity. The MOF‐derived, small‐sized γ‐Al2O3 (M‐Al2O3) catalyst exhibited higher stability and higher activity in the glycerol dehydration reaction than conventional bulk γ‐Al2O3 and nanorod γ‐Al2O3 owing to enriched intercrystal mesopores and an abundance of accessible acid sites. M‐Al2O3 retained its high glycerol conversion (over 80 %) for nearly 200 h, whereas high acrolein selectivity (74 %) was achieved. [ABSTRACT FROM AUTHOR]

Abstract: Catalytic biomass conversion is often hindered by coking. Carbon compounds cover active surface and plug pores, causing catalyst deactivation. Material design at the nanoscale allows tailoring of the catalytic activity and stability. Here, we report a simple synthesis of nanosized ZSM‐5 materials by using a silicalite‐1 seeding suspension. ZSM‐5 crystals were grown from a deionized silica source in the presence of ammonia. By using silicalite‐1 seeds, crystalline ZSM‐5 is synthesized without any structure‐directing agent. This method allows parallel preparation of a range of ZSM‐5 samples, eliminating time‐consuming ion‐exchange steps. Mesoporosity is introduced by formation of intercrystallite voids, owing to nanocrystal agglomeration. The effects of crystal sizes and morphologies are then evaluated in the catalytic dehydration of glycerol to acrolein, with results compared against commercial ZSM‐5. The most active nanosized ZSM‐5 catalysts were five times more stable compared with commercial ZSM‐5, giving quantitative conversion and twice the acrolein yield compared with the commercial catalyst. The influence of the catalyst structure on the chemical diffusion and the resistance to coking are discussed. [ABSTRACT FROM AUTHOR]

We report a facile and general approach for preparing ultrafine ruthenium nanocatalysts by using a plasma-assisted synthesis at <100 °C. The resulting Ru nanoparticles are monodispersed (typical size 2 nm) and remain that way upon loading onto carbon and TiO2 supports. This gives robust catalysts with excellent activities in both organosilane oxidation and the oxygen evolution reaction. [ABSTRACT FROM AUTHOR]

ZrO x /Ni-MnO x /SiO 2 catalyst for CO 2 reforming of methane was prepared using impregnation method, and characterized by in situ DRIFTS, XRD, TEM, XPS and TG. Low-temperature activation of both methane and carbon dioxide was achieved over ZrO x /Ni-MnO x /SiO 2 catalyst, and the catalytic activity was found to be dependent on the reduction temperature. It was found that after being reduced at 550 °C, the ZrO x /Ni-MnO x /SiO 2 catalyst showed relative high content of surface Ni species and small particles of Ni species with a rather narrow particle size distribution. The ZrO x /Ni-MnO x /SiO 2 catalyst reduced at 550 °C showed the highest catalytic activity, with 17.9% and 23.1% initial conversions of CH 4 and CO 2 at the reaction temperature of 500 °C, and the yield of H 2 and CO also reached the maximum value of 9.2% and 14.5%, respectively. In addition to the high catalytic activity, the ZrO x /Ni-MnO x /SiO 2 catalyst also showed a quiet good stability at 500 °C. The initial and stable yields of H 2 and CO were 1.4% and 2.3% at the reaction temperature of 400 °C with the conversion of CH 4 and CO 2 being 2.2% and 4.9%, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mn 1 Zr x O y oxides catalyst with controlled Zr content were prepared. • The reaction rate over Mn 1 Zr 0.10 O y catalyst is 8.3 times over MnO 2. • Propane oxidation on Mn 1 Zr x O y catalyst is revealed to follow the MvK mechanism. Developing efficient non-noble catalysts for low-temperature catalytic oxidation of light alkane is highly desirable and challenging. Herein, we developed a Mn 1 Zr x O y mixed oxide catalyst via a co-precipitation method, finding a significant promotional effect of Zr doping on the catalytic activity of MnO 2 for propane oxidation. It is unraveled that doping Zr into MnO 2 lattice can lead to higher redox ability and oxygen mobility, more oxygen vacancies and enhanced acidity, which are positively responsible for catalytic activity. The kinetic studies and in-situ DRIFTs revealed that the Zr doping does not change the reaction pathway, but facilitates the adsorption and activation of propane and oxygen molecules, thus accelerating the catalytic reaction. In addition, the density functional theory (DFT) calculations further confirmed the contribution of Zr doping in the adsorption of reactant molecules and the formation of oxygen vacancies. Among all, the Mn 1 Zr 0.10 O y catalyst exhibits the highest catalytic activity with the lowest activation energy, and its reaction rate reaches 1.34 μmol g cat. −1 s−1 at 245 °C, 8 times more than that of pure MnO 2 catalyst. Moreover, the catalyst also displays good stability and reusability even under water vapor atmosphere. [ABSTRACT FROM AUTHOR]

This work investigated the yields of monomeric phenols in bio-oil derived from hydrothermal liquefaction of rice straw (RS) in water and ethanol mixtures using a reductive CuZnAl catalyst. Based on the results of an initial analysis, five monomeric phenolic compounds were selected for research due to their higher concentrations, namely phenol, 4-ethyl-phenol, 2-methoxy-phenol, 2-methoxy-4-ethyl-phenol and 2,6-dimethoxy-phenol. The optimized conditions for the production of monomeric phenols can be determined as: 2 g of CuZnAl catalyst, a ratio of 50% ethanol/50% water (v/v), a temperature of 300 °C and a reaction time of 30 min. Results suggested that the maximum yield of total monomeric phenols could reach as high as ~ 26.8% (based on the mass of RS lignin), and that the aqueous phase yielded 95.5% of the monomeric phenols due to the solubilization of the ethanol. The CuZnAl catalyst was recycled five times, and a slight loss in activity was observed and examined using a number of technologies, including inductively coupled plasma, X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and energy dispersive X-ray detection. The low-cost nature of the CuZnAl catalyst makes it an ideal catalyst for the enhancement of monomeric phenols yields in water and ethanol mixtures. [ABSTRACT FROM AUTHOR]

Constructing non-noble robust catalysts for deep catalytic oxidation of obstinate light alkanes at low temperature is of great value and significance. Herein, we designed a facile solvent-thermal-reduction strategy to fabricate an O-vacancy-rich porous MnO 2 nanosheet (MnO 2 −PS) catalyst for propane catalytic oxidation. The abundant vacancies in MnO 2 −PS catalysts can significantly promote its redox ability and oxygen activation capacity, and then provide more active oxygen species with enhanced oxygen mobility and reactivity, thus accelerate the cleavage of C-H bond and the decomposition of intermediates. Meanwhile, benefiting from the porous nanosheet structure, MnO 2 −PS catalyst possesses highly accessible surface and high density of exposed active sites, thus facilitating the adsorption and the activation of reactant molecule. At the same time, the catalyst also exhibits good thermal stability and water resistant ability. This robust and efficient catalytic system may provide some enlightenments for designing feasible catalyst with high-performance for deep catalytic destruction of VOCs. [Display omitted] • O-vacancy-rich porous MnO 2 nanosheets (MnO 2 –PS) catalyst were fabricated through a facile method. • High catalytic performance of propane catalytic oxidation on MnO 2 –PS catalyst was achieved. • The MnO 2 –PS with abundant vacancies exhibits higher density of exposed active sites, higher redox ability and oxygen mobility. [ABSTRACT FROM AUTHOR]

Glycerolysis of triglycerides (corn oil) was carried out over CeO promoted CaO catalysts. CeO was introduced into CaO via the sol-gel combustion method with citrate as the precipitator. A strong interaction between CaO and CeO was revealed by XRD, XPS and Raman results, which results in an increased basic strength and amounts of strong basic sites. Moreover, the lixiviation of CaO in the glycerol at high temperature, which is the key problem in the glycerolysis reaction over CaO-based catalysts, was inhibited significantly. XRD, N adsorption-desorption isotherms and SEM results exhibit introducing CeO increases the surface area, pore volume and pore size of CaO catalysts, which are beneficial to the catalytic activity. The 2CaO-1CeO catalyst with strong basicity and large surface area achieved over 90 % conversion after 1 h while the lixiviated Ca decreased dramatically. Graphical Abstract: [ABSTRACT FROM AUTHOR]

Hybrid polyoxometalate-porphyrin copolymeric films were obtained by the electrooxidation of 5, 15-ditolyl porphyrin ( H 2 T 2 P ) and zinc- β -octaethylporphyrin ( ZnOEP ) in the presence of the Lindqvist-type polyoxovanadates TBA 2 [V 6 O 13 {(OCH 2 ) 3 CNHCO(4-C 5 H 4 N)} 2 ] ( Py-POM-Py ). The resulting films have been characterized by UV–visible absorption spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy and electrochemistry. Electrochemical quartz crystal microbalance was employed to investigate the copolymer mass. [ABSTRACT FROM AUTHOR]

This paper reports the formation of hybrid polyoxometalate-porphyrin copolymeric films obtained by the electro-oxidation of zinc-β-octaethylporphyrin (ZnOEP) in the presence of a functionalized Dawson-type polyoxometalate bearing two pyridyl groups (POMdb3,3, Py-POM-Py) which will be compared to the copolymer obtained from ZnOEP and a dipyridyl compound without POM (ib3,3). The resulting film has been characterized by UV-visible absorption spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. Electrochemical quartz crystal microbalance was employed to investigate the poly-porphyrin-POMs deposition mass. Graphical Abstract[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Four hybrid polyoxometalate-porphyrin copolymer films were obtained by the electrooxidation of zinc octaethylporphyrin in the presence of four different Dawson-type polyoxometalates bearing two pyridyl groups (POM(py)2) with various spacers. The POM monomers were designed around 1,3,5-trisubstituted benzene rings. Two of the substituents of the benzene ring are linked to the pyridyl groups, and the third is connected to the POM subunit. The four monomers vary in the relative positions of the nitrogen atoms of the pyridine rings or in the distance from the carbonyl group. The monomers were fully characterized by 1H, 31P, and 13C NMR spectroscopy, electrospray mass spectrometry, IR and UV/Vis spectroscopy, and electrochemistry. The copolymers were characterized by UV/Vis spectroscopy, X-ray photoelectron spectroscopy, electrochemistry, and AFM. Their photovoltaic performance under visible light irradiation was investigated by photocurrent transient measurements under visible illumination. [ABSTRACT FROM AUTHOR]

An impedance-optimized hierarchical TiO 2 @Fe/C@TiO 2 vesicular carbon microtube is constructed for the first time via coaxial electrospinning and solvothermal method. Benefit from the integration of cavities, highly dispersed magnetic nanoparticles, and dielectric coating, the impedance is effectively improved by dielectric-magnetic synergy. The unique structure simultaneously fulfills a dual-network of micron-scale magnetic interaction and charge transfer, embedding the composite with enhanced magnetic and dielectric loss. The interfacial polarization and multiple reflections further promote microwave absorption. [Display omitted] • 1D vesicular structure was successfully constructed via coaxial electrospinning. • Structural and compositional integration progressively improved impedance. • Strong magnetic-dielectric synergy of quaternary components in this absorber. • Electron holography confirmed magnetic coupling and charge transfer dual-network. Impedance matching (Z) is a key issue requested by high-efficient microwave absorption materials, which remains a major challenge. Lacking magnetic loss capacity and electromagnetic impedance balance, the microwave attenuation capacity of carbon-based absorbers urgently needs to be improved. Herein, a TiO 2 @Fe/C@TiO 2 vesicular carbon microtube was reasonably constructed by coaxial electrospinning. The characteristic impedance was gradually improved by introducing cavities, magnetic Fe particles and dielectric TiO 2 coating. The composite achieves an enhanced microwave performance with a maximum reflection loss of as strong as − 60.98 dB and a broad absorption bandwidth of 4.8 GHz at only 2.0 mm thickness. Such a well-integrated hierarchically vesicular carbon microtube with a tubular porous structure endows the assembly with high magnetic anisotropy and multiple interfaces, further offers the composites: i) the dual-networks of micron-scale 1D anisotropic magnetic coupling and charge conduction, ii) dielectric-magnetic synergy of quaternary components, iii) progressively matched impedance, proved by micromagnetic simulation and electron holography. This finding might have great significance in the impedance matching control of high-performance microwave absorbents. [ABSTRACT FROM AUTHOR]