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Selective hydrogenation of cinnamaldehyde (CAL) to cinnamyl alcohol (COL) was conducted over a series of FeO x -doped Pt catalysts supported on a 15 wt% Al 2 O 3 @SBA-15 composite (15AS). It was found that the addition of FeO x to the catalyst greatly improved its performance. With an optimal Fe/Pt molar ratio of 0.25, the PtFe 0.25 /15AS catalyst reached a maximum reaction rate (defined as moles of converted CAL per gram of Pt per hour) of 13.93 mol g Pt −1 h −1 with 76.9% selectivity to COL. Additionally, the PtFe 0.25 /15AS catalyst afforded the highest TOF value (defined as moles of converted CAL per mole of Pt active sites per second) of 1.54 s −1 . X-ray photoelectron spectroscopy analyses and H 2 temperature-programmed reduction and CO diffuse-reflectance infrared Fourier-transformation spectroscopy studies reveal that there is strong interaction between Pt nanoparticles and Al 2 O 3 @SBA-15 composites and also between Pt and FeO x , resulting in Pt species with a positive charge being dominant in PtFe 0.25 /15AS catalysts. Therefore, Pt species with positive charges, together with FeO x species, are beneficial for preferential adsorption and activation of carbonyl bonds of CAL, so that the activity and selectivity to COL were improved by PtFe x /15AS catalysts ( x represents the Fe/Pt molar ratio). [ABSTRACT FROM AUTHOR]

A comprehensive study was conducted on the synthesis of Cu-MnO x catalysts using a one-pot hydrothermal method followed by a calcination step. These catalysts were thoroughly characterized using techniques such as X-ray diffraction (XRD), X-ray fluorescence (XRF), N 2 physisorption, X-ray photoelectron spectroscopy (XPS), temperature programmed desorption and reduction (TPD and TPR), and advanced transmission electron microscopy (TEM). The results revealed that the Cu:Mn molar ratio of the precursors, Cu(NO 3) 2 and KMnO 4 , had a significant impact on the crystalline structure and morphology of the synthesized samples. A Cu-doped cryptomelane with a nanorod morphology was observed when the Cu:Mn molar ratio was 0.05. Conversely, a mixture of Cu-doped cryptomelane nanorods, Mn 2 O 3 , and Cu 1.5 Mn 1.5 O 4 spinel nanoparticles was formed at molar ratios of 0.1 and 0.25. The catalytic activities of these catalysts for CO oxidation followed the order: 0.25Cu-MnO x ≈ 0.1Cu-MnO x > 0.05Cu-MnO x > cryptomelane. A good correlation was found between the catalytic performance and reducibility of the catalysts under CO atmosphere that can be related to the ability of the samples to activate the CO molecule. The high reducibility of the sample even at room temperature suggest that the CO oxidation over the synthesized Cu-MnO x catalysts may follow a Mars van Krevelen model. [Display omitted] • Tuning of Cu-cryptomelane and Cu x Mn 3−x O 4 spinel phases by adjusting the Cu:Mn ratio. • Optimizing the Cu:Mn ratio leads to a boost in catalytic activity for CO oxidation. • Reducibility, CO activation and phase composition are the key factors for CO oxidation. [ABSTRACT FROM AUTHOR]

The interfacial shear stress between gold and dielectrophoretically assembled single-walled carbon nanotubes can be increased by annealing in N 2 , by e-beam irradiation, or by e-beam deposition of carbon. For the first time this increase has been measured, using a technique developed by this group that is based on NEMS cantilever measurements combined with modeling. Annealing increases the shear stress by more than a factor of 3 over its value of 87 MPa for untreated gold surfaces, while e-beam irradiation increases the shear stress by more than a factor of 2 and carbon deposition increases the shear stress by a smaller amount. [ABSTRACT FROM AUTHOR]

Metal organic-framework MIL-101 and inorganic mesoporous composites Al 2 O 3 @SBA-15 supported Pt catalysts, Pt/MIL-101 and Pt/Al 2 O 3 @SBA-15 catalysts, were prepared and characterized by means of X-ray diffraction (XRD), N 2 adsorption–desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), CO chemisorption and thermo-gravimetric (TG) analysis. Pt nanoparticles were highly dispersed on both supports. In liquid-phase hydrogenation of nitrobenzene, benzaldehyde and their derivatives, the Pt/MIL-101 catalyst was superior to the Pt/Al 2 O 3 @SBA-15 catalyst in water. For liquid-phase hydrogenation of nitrobenzene with the Pt/MIL-101 catalyst, owing to high solubility of nitrobenzene in ethanol, the reaction in ethanol went much faster than that in water, furnishing a turnover frequency (TOF) in ethanol up to 18,053 h −1 , almost triple of that obtained in water under similar conditions. The highest TOF of 25,438 h −1 was obtained in ethanol for hydrogenation of 3-chloro-nitrobenzene with the Pt/MIL-101 catalyst. As for hydrogenation of benzaldehyde series, 2-fluoro-benzaldehyde and 3-fluoro-benzaldehyde gave the highest TOFs of 5146 h −1 and 3165 h −1 in water with the Pt/MIL-101 and Pt/Al 2 O 3 @SBA-15 catalysts, respectively. We deduce that surface property of MIL-101 with high hydrophobicity is helpful to enrich reactants around the Pt/MIL-101 catalyst in water, where nitrobenzene or benzaldehyde and its derivatives have a limited solubility, so that high catalytic performance was achieved with the Pt/MIL-101 catalyst in water. Of particular note is that the Pt/MIL-101 catalyst can be reused at least four times without loss in activity or selectivity. [ABSTRACT FROM AUTHOR]

Highlights: [•] First determination of shear stress between single-walled nanotubes and surfaces. [•] Shear stress is determined based on NEMS experiments and a mechanics model. [•] Demonstrate varying shear stress by a factor of 20 using surface functionalization. [ABSTRACT FROM AUTHOR]

Highlights: [•] MIL-101 metal–organic frameworks as support for Pt nanoparticles. [•] Catalysts are effective for heterogeneous asymmetric hydrogenation of α-ketoesters. [•] Catalysts can be reused several times without distinct loss in activity or ee value. [•] Pt nanoparticles can be well stabilized by MIL-101 metal–organic frameworks. [ABSTRACT FROM AUTHOR]

Although voltage-gated sodium channel (VGSC) activity, upregulated significantly in strongly metastatic human breast cancer cells, has been found to potentiate a variety of in vitro metastatic cell behaviors, the mechanism(s) regulating channel expression/activity is not clear. As a step toward identifying possible serum factors that might be responsible for this, we tested whether medium in which fetal bovine serum (FBS) was substituted with a commercial serum replacement agent (SR-2), comprising insulin and bovine serum albumin, would influence the VGSC-dependent in vitro metastatic cell behaviors. Human breast cancer MDA-MB-231 cells were used as a model. Measurements of lateral motility, transverse migration and adhesion showed consistently that the channel's involvement in metastatic cell behaviors depended on the extracellular biochemical conditions. In normal medium (5% FBS), tetrodotoxin (TTX), a highly specific blocker of VGSCs, suppressed these cellular behaviors, as reported before. In contrast, in SR-2 medium, TTX had opposite effects. However, blocking endogenous insulin/insulin-like growth factor receptor signaling with AG1024 eliminated or reversed the anomalous effects of TTX. Insulin added to serum-free medium increased migration, and TTX increased it further. In conclusion, (1) the biochemical constitution of the extracellular medium had a significant impact upon breast cancer cells' in vitro metastatic behaviors and (2) insulin, in particular, controlled the mode of the functional association between cells' VGSC activity and metastatic machinery. [ABSTRACT FROM AUTHOR]

[Display omitted] • A Mn-doped nickel iron layered double hydroxides (Mn-doped NiFe-LDH) supported on nickel foam was developed, and could act as an efficient bifunctional catalyst for the coupling MOR and HER. • The methanol-to-formate faradaic efficiency was determined to be 99.5 % at an external potential of 1.5 V versus reversible hydrogen electrode. • This electrocatalyst is able to drive a current density of 131.1 mA cm−2 with a decay of merely 12.2 % over continuous 120 h testing in co-electrocatalysis of water/methanol solution. Electrochemical upgrading methanol into value-added formate at the anode in alkaline media enables the boosting production of hydrogen fuel at the cathode with saved energy. To achieve such a cost-effective and efficient electrocatalytic process, herein this work presents a Mn-doped nickel iron layered double hydroxides supported on nickel foam, derived from a simple hydrothermal synthesis. This developed electrocatalyst could act as an efficient bifunctional electrocatalyst for methanol-to-formate with a high faradaic efficiency of nearly 100 %, and for hydrogen evolution reaction, at an external potential of 1.5 V versus reversible hydrogen electrode. Additionally, a current density of 131.1 mA cm−2 with a decay of merely 12.2 % over 120 h continuous long-term testing was generated in co-electrocatalysis of water/methanol solution. Further density functional theoretical calculations were used to unravel the methanol-to-formate reaction mechanism arising from the doping of Fe and/or Mn. This work offers a good example of co-electrocatalysis to produce formate and green hydrogen fuel using a bifunctional electrocatalyst. [ABSTRACT FROM AUTHOR]

There is an urgent need for cost‐effective strategies to produce hydrogen from renewable net‐zero carbon sources using renewable energies. In this context, the electrochemical hydrogen evolution reaction can be boosted by replacing the oxygen evolution reaction with the oxidation of small organic molecules, such as ethylene glycol (EG). EG is a particularly interesting organic liquid with two hydroxyl groups that can be transformed into a variety of C1 and C2 chemicals, depending on the catalyst and reaction conditions. Here, a catalyst is demonstrated for the selective EG oxidation reaction (EGOR) to formate on nickel selenide. The catalyst nanoparticle (NP) morphology and crystallographic phase are tuned to maximize its performance. The optimized NiS electrocatalyst requires just 1.395 V to drive a current density of 50 mA cm−2 in 1 m potassium hydroxide (KOH) and 1 m EG. A combination of in situ electrochemical infrared absorption spectroscopy (IRAS) to monitor the electrocatalytic process and ex situ analysis of the electrolyte composition shows the main EGOR product is formate, with a Faradaic efficiency above 80%. Additionally, C2 chemicals such as glycolate and oxalate are detected and quantified as minor products. Density functional theory (DFT) calculations of the reaction process show the glycol‐to‐oxalate pathway to be favored via the glycolate formation, where the CC bond is broken and further electro‐oxidized to formate. [ABSTRACT FROM AUTHOR]

Solid-state grinding, ultrasonic impregnation and conventional impregnation methods were adopted to synthesize mesoporous composites Al 2 O 3 @SBA-15 supported Pt catalysts for chiral hydrogenation of ethyl 2-oxo-4-phenylbutyrate after modified with cinchonidine. Compared with Pt/SBA-15 or Pt/alumina catalyst, Pt/Al 2 O 3 @SBA-15 catalysts afforded better results when alumina loading in Al 2 O 3 @SBA-15 composites reached above 15 wt.%. Nevertheless, the catalytic performance of Pt/Al 2 O 3 @SBA-15 catalysts was affected by preparation methods for Al 2 O 3 @SBA-15 composites. Ultrasonic impregnation of SBA-15 with an aqueous solution of aluminum nitrate led to uniformly dispersed Al 2 O 3 @SBA-15 composites and then enhanced the interaction between SBA-15 silica and alumina. Correspondingly, the Pt/Al 2 O 3 @SBA-15 catalyst prepared by this method showed the best results (up to 11,928 h −1 TOF and 87.9% ee) and could be reused for several times. Based on the spectroscopic characterizations, we deduced that the acidity of the composites, the Pt particle size and dispersion, and the electronic properties of Pt particles played vital roles in determining the catalytic performance. [ABSTRACT FROM AUTHOR]

Ru nanoparticles entrapped in ordered mesoporous carbons (CMK-3) served as an efficient and reusable catalyst for liquid-phase hydrogenation of benzaldehyde and its derivatives under our tested conditions (medium hydrogen pressure, room temperature, water as solvent). The Ru nanoparticles can be well stabilized by CMK-3 ordered mesoporous carbons so that the Ru leaching was below the detection limit of ICP-AES. Therefore, the Ru/CMK-3 catalyst can be used for at least five times without distinct loss in activity or selectivity for the hydrogenation of benzaldehyde. It is worthy of note that the Ru/CMK-3 catalyst was more efficient than the commercial Ru/C and homemade Ru/AC catalyst for the liquid-phase hydrogenation of benzaldehyde. The Ru/CMK-3 catalyst can also catalyze the liquid-phase hydrogenation of nitrobenzene and its derivatives with high conversions and excellent selectivities under optimal conditions. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Abstract: A series of TiO2@SBA-15 composites with different TiO2 loadings have been synthesized through hydrolysis of tetrabutyl orthotitanate via a facile sol–gel method in the presence of SBA-15 mesoporous silica. The TiO2@SBA-15 composites retain the mesostructure of the SBA-15 host, and TiO2 is highly dispersed and uniformly coated. The TiO2@SBA-15 composites serve as remarkable supports for Pt nanoparticles, which can be applied efficiently to the liquid-phase hydrogenation of benzaldehyde, its derivatives, and other unsaturated compounds under mild conditions. Of particular note is that the Pt/TiO2@SBA-15 catalysts can be reused several times without distinct loss in activity or selectivity. The more electron-deficient surface state, together with the structural and physicochemical features of Pt/TiO2@SBA-15 catalysts, would improve the catalytic activity and reusability toward the liquid-phase hydrogenation of unsaturated compounds. [Copyright &y& Elsevier]

[Display omitted] • Synthesis of praseodymia nanorods and nanoparticles. • Excellent multi-funtional oxidase-like activities of praseodymia nanomaterials. • Colorimetric sensing of L-cysteine and fluoride using praseodymia nanorods. The ability to mimic protein-based oxidase with multi-functional inorganic nanozymes would greatly advance biomedical and clinical practices. Praseodymia (PrO x) nanorods (NRs) and nanoparticles (NPs) have been synthesized using hydrothermal and precipitation methods. Both PrO x catalysts with different morphologies exhibit significantly higher oxidase-like activities (Michaelis-Menten constant K m ≤ 0.026 mM) than commercial PrO x and most so-far-reported artificial enzymes. One of the substrates, dopamine, can be oxidized and further polymerized to generate polydopamine in acidic conditions. Akin to CeO 2 , which is a well-studied nanozyme, a different mechanism involving holes+, oxygen vacancies and oxygen mobility over PrO x catalysts has been proposed in this work. However, fluoride ions were found to impose opposite effects on the oxidase-mimicking activity of PrO x and CeO 2 , implying a promising path for the exploration of new nanozymes. In support of this, PrO x was further applied in colorimetric sensing of L-cysteine and fluoride with high sensitivity. [ABSTRACT FROM AUTHOR]

Monometallic Au, Pd and bimetallic Au-Pd catalysts supported on a Ce 0.62 Zr 0.38 O 2 mixed oxide have been synthesized by the sol-immobilization method. An in-depth Scanning-Transmission Electron Microscopy (STEM) study has been performed to reveal the structural and chemical nature of the metal nanoparticle system present in these catalysts. Attention has been paid both to the evolution of the particle size distribution and the degree of Au-Pd interaction as a function of the treatment used to activate the catalysts. This characterization work has been complemented by results coming from other macroscopic techniques like Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES), N 2 physisorption, Temperature Programmed Oxidation (TPO) or X-ray Photoelectron Spectroscopy (XPS). The whole set of characterization data evidences the intrinsic structural complexity of this type of bimetallic systems, in which a fraction of monometallic Au, monometallic Pd and bimetallic nanoparticles of varying compositions coexist. This picture, which clearly contrasts with other much more homogeneous situations described in previous literature on bimetallic catalysts, also indicates the requirement of combining both atomic scale and macroscopic techniques to understand the structure of these catalysts. Concerning catalytic performance, a synergistic effect between Au and Pd has been observed in the selective oxidation of benzyl alcohol on ceria-zirconia. Moreover, the catalytic activity of these bimetallic Au-Pd catalysts is higher than that on other commonly used supports, such as activated carbon or carbon nanotubes. The treatments in oxidative and inert atmospheres at 250 °C improve the catalytic activity with respect to the fresh, un-pretreated, catalyst. Subsequent reduction of the oxidized bimetallic catalyst leads to an activity similar to that of the fresh catalyst, which is reduced at room temperature with H 2 bubbles. [ABSTRACT FROM AUTHOR]

• Ni x Co y Se 2 nanoparticles with controlled Ni/Co ratio are produced. • They were used for ethanol conversion into a valuable chemical and hydrogen. • Optimized electrocatalysts deliver 0.34 mmol cm-2h−1 of acetate from ethanol oxidation. • Co enhances ethanol adsorption and decreases the dehydrogenation energy barrier. The energy efficiency of water electrolysis is limited by the sluggish reaction kinetics of the anodic oxygen evolution reaction (OER). To overcome this limitation, OER can be replaced by a less demanding oxidation reaction, which in the ideal scenario could be even used to generate additional valuable chemicals. Herein, we focus on the electrochemical reforming of ethanol in alkaline media to generate hydrogen at a Pt cathode and acetate as a co-product at a Ni 1-x Co x Se 2 anode. We first detail the solution synthesis of a series of Ni 1-x Co x Se 2 electrocatalysts. By adjusting the Ni/Co ratio, the electrocatalytic activity and selectivity for the production of acetate from ethanol are optimized. Best performances are obtained at low substitutions of Ni by Co in the cubic NiSe 2 phase. Density function theory reveals that the Co substitution can effectively enhance the ethanol adsorption and decrease the energy barrier for its first step dehydrogenation during its conversion to acetate. However, we experimentally observe that too large amounts of Co decrease the ethanol-to-acetate Faradaic efficiency from values above 90% to just 50 %. At the optimized composition, the Ni 0.75 Co 0.25 Se 2 electrode delivers a stable chronoamperometry current density of up to 45 mA cm−2, corresponding to 1.2 A g−1, in a 1 M KOH + 1 M ethanol solution, with a high ethanol-to-acetate Faradaic efficiency of 82.2% at a relatively low potential, 1.50 V vs. RHE, and with an acetate production rate of 0.34 mmol cm−2 h−1. [ABSTRACT FROM AUTHOR]

• The fixation of CO 2 by chemical conversion is needed to reduce CO 2 in the atmosphere. • The coupling of CO 2 to get cyclic carbonates has obtained extensively attention. • The catalysts are mandatory for the reaction owing to thermal stable nature of CO 2. • The catalysts of MOFs and POPs about organic compounds are reviewed in detail. CO 2 as the C1 building blocks, plays an important role in the carbon cycle of natural. Various efforts have been devoted to the capture and utilization of CO 2 with physical, biomass and chemical approaches. Among these methods, the coupling of CO 2 with epoxides to prepare cyclic carbonates (CC) is considered to be one of the most promising approaches for conversing CO 2 to valuable chemicals. Considering the strong economic potential of CC , it is urgently needed to improve the synthesis conditions and decrease production costs. However, CO 2 is a thermodynamically stable molecule, the use of catalysts is therefore indispensable for activation and facilitating the CO 2 /epoxides coupling reaction in a selective manner under mild conditions. This review covers two kinds of homogeneous catalysts Lewis acid plus nitrogen/phosphorus organic compounds, and their corresponding heterogeneous catalysts mainly focusing on metal organic frameworks and porous organic polymers for the coupling reactions of CO 2 and epoxides. Finally, an overview on the future trend of CC synthesis with alkene instead of epoxides to couple CO 2 under relative mild conditions would be displayed. [ABSTRACT FROM AUTHOR]