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Core–shell-structured SBA-15@MgAl 2O 4 (abbreviated as S@MA) was prepared by homogeneous precipitation through sol–gel method. The effects on the properties of S@MA as a supporting material have been investigated in comparison with MA and SBA-15. The results showed that the pore structure was changed, the acid sites were introduced, and the surface properties were improved by the construction of the core-shell-structured S@MA. Then, these materials were used as the carrier for the catalysts by impregnation method. Moreover, in PtSnNa/S@MA, these modifications not only decreased the size of surface Pt ensembles, but also changed the interfacial character between metal and support. In addition, compared to PtSnNa/MA, the capacity of the catalyst which supports on S@MA to accommodate coke was improved and the carbon deposit on PtSnNa/S@MA was migrated from the active metal to the carrier. These intriguing results are attributed to larger surface area and the appearance of the acid sites in S@MA. [ABSTRACT FROM AUTHOR]

A woman with coronavirus disease in her 35th week of pregnancy delivered an infant by cesarean section in a negative-pressure operating room. The infant was negative for severe acute respiratory coronavirus 2. This case suggests that mother-to-child transmission is unlikely for this virus. [ABSTRACT FROM AUTHOR]

Background: Advanced stage laryngeal squamous cell carcinoma (LSCC) presents a poor prognosis; thus, there is a great need to identify novel prognostic molecular markers. Procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 (PLOD2) is thought to be a novel prognostic factor in several cancers, but its role in LSCC remains unknown. Cancer stem cells (CSCs) are responsible for most instances of tumor recurrence and the development of drug resistance and have been proven to be present in head and neck cancers. Our preliminary study indicated that PLOD2 was elevated in LSCC tissues; therefore, we hypothesized that PLOD2 is related to the prognosis of LSCC patients and aimed to explore the role and underlying mechanism of PLOD2 in LSCC.Methods: We validated the prognostic role of PLOD2 in 114 LSCC patients by immunohistochemistry. Stable PLOD2-overexpressing Hep-2 and FaDu cells were established and assessed by molecular biology and biochemistry methods both in vitro and in vivo.Results: We confirmed that PLOD2 overexpression was correlated with poor prognosis in LSCC patients. PLOD2 overexpression strengthened the CSC-like properties of Hep-2 and FaDu cells, activated the Wnt signaling pathway and conferred drug resistance in LSCC in vitro and in vivo.Conclusions: We found that PLOD2 could serve as a prognostic marker in patients with LSCC and confer drug resistance in LSCC by increasing CSC-like traits; in addition, a Wnt-responsive CSC pathway was identified. [ABSTRACT FROM AUTHOR]

Novel SSZ-39 zeolite-based Ru catalysts were synthesized by impregnation on as-synthesized metallic and protonated SSZ-39 and a one-pot synthesis strategy. The study focused on the influence of the SSZ-39 zeolite characteristics and catalyst preparation method type toward levulinic acid (LA) selective conversion to γ-valerolactone (GVL) under relatively mild reaction conditions (150 °C, 4 h and 2 MPa of H 2 with H 2 O and THF as solvents). Catalysts exhibited excellent catalytic efficiency (100 % LA conversion and 98.3 % GVL selectivity) and remarkable hydrothermal stability. The results revealed a correlation between excellent catalytic activity and the structural features of the synthesized catalysts, predominantly dependent on their appropriate surface acidity (strong Lewis acid sites) and enhanced electronic interaction between Ru species and SSZ-39. The one-pot method promoted the formation of mesopores besides the zeolitic micropores present in SSZ-39; therefore, the catalyst prepared by the one-pot method (Ru/SSZ-39) showed purer SSZ-39 crystallites and a slightly larger catalytic surface area of 439 m2/g than the original zeolite surface area of 424 m2/g. In addition, the original zeolite crystals retained their morphology as spherical aggregates and remained unaffected by Ru impregnation on the metallic or protonated support during the synthesis of Ru/Na-SSZ-39 and Ru/H-SSZ-39 catalysts, respectively. Notably, it has been demonstrated that SSZ-39 zeolite effectively acts as a support for the preparation of Ru catalyst in biomass conversion reactions. Moreover, the reused catalyst exhibited consistent activity over six cycles, maintaining its structural framework without significant loss in activity. [Display omitted] • Ru/SSZ-39 zeolite catalysts were achieved using impregnation and one-pot method synthesis methods. • The one-pot synthesis yielded purer SSZ-39 crystallites and a larger catalytic surface area. • The addition of Ru generates intermediate acidic sites, enhancing catalytic performance toward hydrogenating LA to GVL. • SSZ-39 zeolite effectively acts as a Ru catalyst support in biomass conversion reactions. [ABSTRACT FROM AUTHOR]

The selective conversion of levulinic acid (LA) obtained from lignocellulosic biomass represents a crucial pathway for producing the key value‐added chemical compound γ‐valerolactone (GVL). Herein, we constructed a series of Pt‐based titanium‐silicalite‐1 (TS‐1) bifunctional catalysts modified with rare earth metal Ce through a simple spin‐coating impregnation method, and the catalytic performance was significantly improved compared to the unmodified Pt1.2/TS‐1. Pt0.7‐Ce0.5/TS‐1 exhibited the best aqueous‐phase catalytic activity (with a GVL yield of 99.4%). The introduction of CeOx can reduce the particle size of Pt nanoparticles and promote the formation of electron‐rich Pt species while delivering abundant oxygen vacancies (OV) for the catalysts. The characterization and testing results highlight the synergistic effect of OV and electron‐rich Pt sites on the oriented adsorption and selective hydrogenation of LA, providing new insights into constructing more efficient noble metal‐based zeolite catalysts for biomass conversion. [ABSTRACT FROM AUTHOR]

Piperidinium‐based ionic liquids (ILs) were synthesized under mild conditions by coordinating N‐alkyl‐N‐methylpiperidinium bromide ([Pip1,x]Br) with anhydrous AlCl3. The weak basicity of N‐methylpiperidine had little impact on downstream problems from proton impurities and catalyst poisoning. The results of Fourier transform infrared (FT‐IR), electrospray ionization mass spectrometry (ESI‐MS), and nuclear magnetic resonance (27Al NMR) confirmed that the active components in [Pip1,x]Br‐2AlCl3 (χ = 0.67) were [Al3Cl9Br]− and [Al2Cl6Br]−. Besides, the reaction performance of [Pip1,8]Br‐2AlCl3 under different conditions was carried out by single‐factor experiment and further confirmed by orthogonal experimental method. Among these reaction conditions, the optimal combination was the reaction temperature of 40°C, ILs/O molar ratio of 0.2:1, px/O molar ratio of 12:1, and the reaction time of 30 min. Furthermore, [Pip1,8]Br‐2AlCl3 had excellent stability and can be recycled 14 times. It was the high‐efficiency catalytic activity and prominent recyclability that made continuous industrial production possible. [ABSTRACT FROM AUTHOR]

Catalysts based on different halo‐alkanes structures with durable catalytic performance were synthesized and applied to the Friedel–Crafts alkylation of long‐chain alkenes (mixed C16–24 olefins) with toluene. Surprisingly, compared with the usual industrial catalysts (~10 runs), the cyclic times of the ionic liquid (IL) catalysts reached up to 24 runs, which greatly promotes the industrialization process. Then, Lewis acids of catalysts with different precursor/AlCl3 molar ratios were investigated and a close relation was discovered between the Lewis acid and catalytic activity. In addition, a comparison of the different halo‐alkanes structures about those catalysts was made. The results showed that the [C6Et3N]Cl–AlCl3 had the strongest Lewis acid, corresponding to the highest catalytic performance. Also, the structures of precursors and the specific gravity and active site species of catalysts were investigated by Fourier transform infrared and Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR). Meanwhile, the various parameters (catalyst dosage, toluene/olefin molar ratio, reaction temperature and reaction time) of long‐chain alkenes alkylation with toluene were studied. Finally, under the optimized reaction conditions, the conversion and selectivity of long‐chain alkenes alkylation reached 99.92 and 32.99%, respectively. [ABSTRACT FROM AUTHOR]

• Fe 2 TiO 5 /rGO composites were synthesized by a solvothermal method. • The cycling stability of Fe 2 TiO 5 is improved due to introduction of rGO. • The rGO provides buffer space to alleviate volume expansion of Fe 2 TiO 5. Iron-titanium bimetallic oxide, Fe 2 TiO 5 (FTO), is anticipated to exhibit superior electrochemical properties due to its high theoretical capacity. However, the practical large-scale utilization of FTO is severely hindered by its substantial capacity fading and subpar cycling performance. In this work, we propose a strategy to improve the electrochemical properties of FTO by carbon coating. To implement this strategy, we synthesize FTO nanoparticles (FTO NPs) coated with reduced graphene oxide (rGO) by a solvothermal method. When used as anode materials in lithium-ion batteries, FTO/rGO composite demonstrates a higher specific capacity (498.2 mAh g−1 after 100 cycles) than pristine FTO NPs, which is ascribed to the addition of rGO. The rGO with excellent conductivity facilitates efficient electron and ion transportation, and the composite structure of FTO NPs wrapped with rGO provides buffer space to alleviate the volume expansion during the charge/discharge process. [ABSTRACT FROM AUTHOR]

[Display omitted] • Iron compounds/polyacrylonitrile carbon fibers were prepared by electrospinning a mixed solution of polyacrylonitrile (PAN) and iron(III) acetylacetonate [Fe(acac) 3 ]. • The phase-transformation mechanism and the associated chemical reactions during the pre-oxidation process have been clarified. • The cyclization of PAN takes place during the pre-oxidation process, and the crystalline iron acetylacetonate in PAN fibers transform into amorphous metal oxides, i.e. , FeO and Fe 2 O 3. Low-temperature pre-oxidation of electrospun metal-compound-incorporated carbon fibers can involve phase transitions and chemical reactions. However, their mechanics remain unclear. In this work, a mixture of polyacrylonitrile (PAN) and iron acetylacetonate is subjected to electrospinning followed by a pre-oxidation process at 230 °C, producing PAN fibers loaded with iron compounds. Our detailed investigations shed light on the mechanisms of phase transitions and associated chemical reactions during the pre-oxidation process. Our findings reveal that PAN undergoes cyclization during pre-oxidation, and that crystalline iron acetylacetonate within PAN fibers transforms into amorphous FeO and Fe 2 O 3. [ABSTRACT FROM AUTHOR]

Imidazole (IMI)-based polyethylene glycol monomethyl ether (MPEC-IMI) as a novel green corrosion inhibitor was synthesized to protect the Q235 steel in 0.5 M HCl corrosive medium at 318 K. The inhibition performance of MPEC-IMI was investigated by weight loss measurement, the electrochemical method (Tafel and EIS) and surface analysis (SEM and EDX). The results reveal that the MPEC-IMI shows enhanced anticorrosion performance for carbon steel, which is attributed to the formation of the adsorptive protection film on the surface, and the type of adsorption basically obeys the Langmuir monolayer adsorption. Furthermore, when the concentration of MPEC-IMI is 300 mg L−1, the corrosion inhibition efficiency can reach up to 92.00%. In support of further study of the corrosion inhibition behavior by virtue of quantum chemical calculation and molecular dynamics simulations, the results show that the MPEC-IMI molecule has high reactivity and strong interaction on the iron surface. [ABSTRACT FROM AUTHOR]

Objectives: We describe a survival nonstimulated in vivo canine phonation model using distending laryngoscope, cramp frame, and constant humidified glottal airflow to elicit phonation. Methods: Five beagle dogs were involved in this study. One cuffed endotracheal tube was placed below the glottis through the tracheotomy and delivered humidified airflow to the glottis. Arytenoids approximation was maintained using a clamp under the distending laryngoscope. Acoustic and aerodynamic parameters were measured using synchronous signal collection system and analysis software. Vocal oscillation also was examined using stroboscope laryngeal imaging. Results: For the nonstimulated in vivo phonation animal, the sound intensity and fundamental frequency were 78.3 ± 6.8 dB and 127.6 ± 29.2 Hz in the first experiment and 82.9 ± 6.6 dB and 175.2 ± 4.4 Hz 4 weeks later. The aerodynamic analysis revealed the mean subglottal phonation threshold pressure (PTP) and phonation threshold flow (PTF) were 8.5 ± 4.0 cmH20 and 683.0 ± 356.4 mL/s in the first experiment and 16.1 ± 8.6 cmH20 and 384.8.0 ± 230.6 mL/s in the second experiment 4 weeks later. Stroboscope image revealed sustained vocal vibration during great airflow delivery to glottis in the phonation animal model. Conclusions: We developed a survival nonstimulated in vivo phonation canine model that allows the study of long-term animal phonation study as its own control. [ABSTRACT FROM AUTHOR]

Cross-linked poly acidic ionic liquids (MPM-C 6 V-SO 3 CF 3 -IL) with mesoporous and macroporous network structure have been synthesized in different solvents. The novel solid acid catalyst with special network structure has a large surface area (103.83 m 2 /g), large pore volume (0.72 cm 3 /g) and abundant mesopores and macropores, which help to improve the contact between active site and reactants. Catalytic performance of catalyst was investigated through alkylation of o -xylene and styrene. Different reaction parameters specifically solvent on obtained catalyst and production of PXE were systematically investigated. Under optimal reaction conditions (reaction time was 3 h, reaction temperature was 120 °C, catalyst amount was 0.17 g (0.5 wt%), and o -xylene/styrene mass ratio was 7.5:1), a high conversion of styrene (100%) and 1,2-diphenylethane (PXE) yield of 99.67% was obtained, which is superior to commercial acid in liquid and even previous acids synthesized by our own group. Moreover, catalyst could keep relatively high thermostability under reaction and are easy to be separated and recycled from the solution, which are critical for heterogeneous solid catalysts. Thus, this novel catalyst can be potentially applied in other acidic reactions. [ABSTRACT FROM AUTHOR]

A simple and effective one-step method was proposed for the fabrication of dual-mesoporous silica, which was templated by alkoxysilyl-functionalized ionic liquid and cetyltrimethyl ammonium bromide (CTAB), with potential application in alkylation of o -xylene and styrene. Ionic liquid act as both template and silica source in this system. The influence of pH of solvent and concentration of alkoxysilyl-functionalized ionic liquid to the morphology of obtained silica was studied in detail. The results showed that the as-prepared silica materials with core-shell or hollow structure could be fabricated by adjusting the pH and ionic liquid concentration, which is strongly related to the unique features of alkoxysilyl-functionalized ionic liquid with organic silicon chain. The possible mechanism was proposed based on the interaction between ionic liquid and CTAB. This new method is also applicable to synthesize the other hierarchical porous silica materials by using organic silyl functional ionic liquid. [ABSTRACT FROM AUTHOR]

Well-dispersed Pt–Zn nanoclusters encapsulated in the mesopores of SAPO-11 were prepared by a one-pot synthesis method using dipropylamine to anchor metal nanoclusters to the support. The phenomenon of metal leaching or agglomeration can be effectively avoided. It exhibits high stability after 36 h of reaction time, with a GVL yield above 80%. Based on the zeolite SAPO-11, a catalyst structure of zeolite-coated metal nanoclusters was constructed. Due to the chemisorption between platinum and the lone pair of electrons in the nitrogen atoms of organic amines, the platinum and zinc metal nanoclusters combined through a strong synergistic effect were confined within the inner space of supports. The structure of molecular sieve encapsulating metal components can effectively promote the reaction due to the proximity of metal sites and acid sites. Pt–Zn nanoclusters can promote the formation of silicon islands, and in the framework structure, moderately strong acid sites can be generated from the boundaries of silicon islands, thereby realizing the controllable regulation of zeolite frameworks. This encapsulation structure can effectively avoid metal leaching or metal agglomeration. Furthermore, the catalyst exhibited high stability after 36 h of reaction, i.e., 6 catalytic repetitions with a GVL yield higher than 80% and no change in the crystal structure of the support. [ABSTRACT FROM AUTHOR]

Platinum-based alloy materials as effective cocatalysts in improving the performance of photocatalytic H 2 production have raised great interest. Herein, a facile strategy of chemical reduction is established to synthesize bimetallic PtNi nanoparticles on 2D g-C 3 N 4 nanosheets with excellent photocatalytic activity. The addition of PtNi nanoparticles can provide new H+ reduction sites and increase more active sites of the material. The synergistic effect between PtNi alloy nanoparticles and 2D g-C 3 N 4 nanosheets can regulate electronic structure, narrow the band, accelerate charge transfer efficiency and inhabit the recombination of photo-induced electron (e−) and hole pairs (h+), contributing to the improvement of hydrogen evolution activity. The optimal hydrogen evolution rate of Pt 0.6 Ni 0.4 /CN shows higher hydrogen evolution rate (9528 μmol·g−1·h−1), which is 13.1 times than that of pure g-C 3 N 4 nanosheets. Besides, a possible mechanism of photocatalytic hydrogen generation has been brought up according to a series of physical and chemical characterization. This work also provides a potential idea of developing cocatalysts integrating metal alloys with 2D g-C 3 N 4 nanosheets for promoting photocatalytic hydrogen evolution. The integration of bimetallic PtNi nanoparticles and g-CN can inhabit the recombination of photo-induced electron (e−) and hole pairs (h+), contributing to promoting hydrogen evolution activity. [Display omitted] • Pt x Ni 1-x /CN catalysts were synthesized by a facile method of chemical reduction. • The synergistic effect of PdNi alloy could accelerate charge transfer efficiency. • The Pt 0.6 Ni 0.4 /CN showed the highest H 2 generation activity. • A possible mechanism of photocatalytic hydrogen production was proposed. [ABSTRACT FROM AUTHOR]

In this work, superhydrophobic and superlipophilic Ni–Al LDH/cellulose membranes with flower-like microscopic surface morphology were successfully prepared at low cost. The rough surface morphology was obtained by in situ growth of Ni–Al LDH (layered double hydroxide) on cellulose membranes, which were then modified with hexadecyltrimethoxysilane (HDTMS) for surface hydrophobicity. In addition, the effects of different amounts of HDTMS were investigated and optimised. The results showed that the water contact angle of the membrane produced was as high as 157° and the oil contact angle was 0°. The membrane has a high oil–water separation efficiency (99.6%) and flux (up to a maximum of 1412 L m−2 h−1). The separation efficiency, permeate flux and oil and water contact angles could be maintained at a high level under adverse conditions, and the water contact angle was above 150° after repeated recycling, which has good recyclability and is promising for oil–water separation. [ABSTRACT FROM AUTHOR]

Exploration of levulinic acid (LA) hydrogenation to γ‐valerolactone (GVL) contributes to the conversion from carbohydrates to valuable fuels and chemicals. Here, we obtained a series of ultra‐small PtNix bimetallic composite catalysts encapsulated in silicalite‐1 zeolite (S‐1) via a one‐pot synthesis strategy protected by tetra(p‐carboxyphenyl)porphyrin (TCPP) ligands. The catalytic results showed that PtNi3@S‐1 (TCPP) exhibited the most active catalytic performance (95.7% LA conversion and 93.8% GVL selectivity) under optimized conditions. The characterization results indicate that ligand modification and bimetallic synergy play an important role in enhancing the catalytic activity. The introduction of TCPP provides a guarantee for the homogeneous encapsulation of PtNi3 in S‐1 zeolite at sub‐nanometer size. The electronic interaction of PtNi bimetallic, high dispersibility of active components, improved surface acidity and excellent stability co‐contribute to the satisfactory hydrogenation activity. [ABSTRACT FROM AUTHOR]

Overcoming the low charge transfer efficiency and poor photothermal stability of halide perovskite quantum dots (QDs) is the booster to achieve photocatalytic applications. In this paper, the Pt2+-doped CsPbBr 3 QDs/two-dimensional accordion-like Ni-MOF (CPPB QDs/Ni-MOF) composite was firstly synthesized by fixing the CPPB QDs into the pores of Ni-MOF. Electron separation and transfer efficiency were analyzed by PL spectra and electrochemical data. The photocatalyst exhibited outstanding photocatalytic performance in hydrogen (H 2) evolution. The optimal H 2 evolution efficiency of the composite reached 153.6 μmol h−1, which was about 9 times than that of pure Ni-MOF and remained 134.8 μmol h−1 after the cycle test. The splendid efficiency could be benefited from the advantages of 2D layered structure of Ni-MOF and the high charge separation and transmission efficiency of CPPB QDs. Finally, the mechanism of electron migration and additional electron transfer channels between composite interfaces was further demonstrated by density functional theory (DFT) calculations. The present work opens up a novel perspective for photocatalytic applications of doped halide perovskite QDs/Ni-MOF nanocomposites. • The Pt2+-doped CsPbBr 3 QDs/Ni-MOF nanocomposites have first been successfully fabricated. • The resultant nanocomposites exhibit excellent photoactivity on H 2 production. • The enhanced thermal stability and photocatalytic activity of the nanocomposites was discussed. [ABSTRACT FROM AUTHOR]

Platinum (Pt) is considered as the preferred metal catalyst for methanol oxidation reactions. However, the application prospects of Pt catalysts are limited due to the inherent scarcity and cost. Enabling a trace amount of Pt to exert satisfactory catalytic activity and durability has become a key issue in designing electrocatalysts. Here, Ru-doped PtSn alloy nanoplates (PtSn@Ru NP) with an average particle size of less than 5 nm were controllably synthesized by adjusting the Pt–Sn atomic ratio. Compared with Ru-doped PtSn alloy nanospheres (PtSn@Ru NS/C, 714.7 mA/mg Pt), PtSn bimetallic nanoplates (PtSn NP/C, 880.2 mA/mg Pt) and commercial Pt/C (299.6 mA/mg Pt), the prepared PtSn@Ru NP/C (1105.1 mA/mg Pt) exhibited an extraordinary methanol oxidation mass activity. Furthermore, the peak oxidation current retention of PtSn@Ru NP/C was as high as at 87.5% after 1000 accelerated durability tests. The significantly enhanced catalytic performance and durability were attributed to the synergistic effect of the alloy components and morphological advantages. This work has led us to think more deeply about the constitutive relationship between structure and performance. [Display omitted] • Ru-doped PtSn alloy nanoplates with uniform dimensions (5 nm) were prepared. • Ru doping promoted the efficient conversion of the intermediate products. • The synergistic effect of Sn and Pt improved the stability of the catalyst. • PtSn@Ru NP/C exhibited excellent methanol oxidation mass activity (1105.1 mA/mg Pt). [ABSTRACT FROM AUTHOR]

In this study, polysiloxane@CeO@PMMA microspheres were successfully synthesized by controllable one-pot process, in which CeO nanoparticles were stabilized in the surface of PMMA nano/microsphere using an in situ precipitation method. The core-shell structure of the synthesized product were confirmed by FT-IR, XRD and electronic microscope analysis. The size of polysiloxane@CeO@PMMA nano/microspheres were about 550 nm via microscopy analysis. Moreover, the novel hybrid nanocomposites eliminated the yellowish coloration problem of CeO and had good dispersibility. In addition, the transmittance of the multifunctional films based on polysiloxane@CeO@PMMA microspheres owned good transmittance of visible light and can block harmful UV rays, which can be attributed to nano-CeO accession. Hence, such green synthesized route can be considered as a simple common method for preparing UV-shielding multifunctional materials. [ABSTRACT FROM AUTHOR]

Pt nanocatalysts have received enthusiastic attention in the field of clean energy technologies due to their high catalytic activity and selectivity. The growth size and dispersion of Pt particles play significant effects on the reaction activity, especially in high temperature catalytic reactions where catalysts are prone to deactivation due to agglomeration and sintering of Pt particles. Herein, the Pt nanoparticles were effectively stabilized on AIPO‐18 molecular sieve by a biomolecule‐mediated green synthesis method. Based on the biocompatibility and electrostatic synergy of carboxymethyl chitosan (CMC), a high degree of Pt nanoclusters dispersion in AIPO‐18 zeolites was achieved. The hydroconversion of levulinic acid (LA)was carried out at 160°C and 2 MPa hydrogen pressure, and the LA conversion of Pt/AIPO‐18 (5CMC) reached 95.2% and the selectivity of γ‐valerolactone (GVL) was 97.9% after 2 h. Pt/AIPO‐18 (5CMC) exhibited satisfactory results that superior to the initial reactivity of Pt/AIPO‐18 (0CMC) after five runs. [ABSTRACT FROM AUTHOR]

Abstract: The effect of the different competitive adsorbates (acetic acid, hydrochloric acid and nitric acid) on the catalytic performances of PtSnK/γ-Al2O3 catalyst for isobutane dehydrogenation has been investigated by reaction tests and some physicochemical characterizations such as XRD, nitrogen adsorption, XRF, NH3-TPD, TEM, TPR and H2 chemisorption. It was found that the presence of hydrochloric acid during the process of catalyst preparation could not only promote the distribution of metallic particles, but also produce the strong interactions between Sn species and support, as well as Pt and tin oxides. Thus, more amounts of tin could exist in oxide states, which was advantageous to the anchoring of Pt active sites and the dehydrogenation reaction. In our experiments, the catalyst prepared in HCl medium exhibited the highest reaction activity and stability. By increasing the reaction temperature (600°C), the use of this adsorbate could also improve the catalytic performance. As compared with this catalyst, relatively poor distribution of metallic particles was found due to the existing steric effect of acetic acid, and the catalyst acidity increased when the used adsorbate was nitric acid. Finally, a model for the influence of hydrochloric acid as competitive adsorbate was proposed. [Copyright &y& Elsevier]

Abstract: The influence of the amount of alumina binder on the catalytic properties of PtSnNa/AlSBA-15 catalysts for propane dehydrogenation was investigated. BET surface area measurement, catalyst particle mechanical strength, solid-state 27Al MAS NMR spectroscopy, hydrogen chemisorption, NH3-TPD and XPS were used to characterize the catalysts. It can be observed that the mechanical strength of the agglomerated catalyst was higher than that of the nonagglomerated one. Among these catalysts studied, the PtSnNa/AlSBA-15 catalyst bound with 20wt.% alumina binder showed the best catalytic performance in terms of propane conversion and selectivity to propene. The high catalytic performance may be due to relatively good Pt metal dispersion and/or the strong interaction between Pt and Sn, which were attributed to an increase in Al(IV) and Al(VI) species for the agglomerated catalyst. [Copyright &y& Elsevier]

Currently, two-dimensional (2D) layered transition metal chalcogenides (TMCs), especially MoS2, are attracting widespread attention in the field of water electrolysis. Unfortunately, the catalytic activity of MoS2 is limited to a few edge sites and by its low conductivity. Herein, MoS2/NiS heterostructures possessing a flower-like morphology were constructed via an accurate thermal treatment process to realize precise interface modification. As expected, through the adjunction of a certain amount of polyvinylpyrrolidone, NiS grew uniformly on the surface of MoS2 nanosheets, thereby forming a large number of visual lattice fringes with a specific interplanar spacing, which promoted a higher electron-transfer efficiency. The better electron-transfer efficiency resulted in a better hydrogen evolution reaction performance, providing an overpotential of 158 mV at 10 mA cm−1, a Tafel slope of 128.1 mV dec−1, and significantly long-term durability. Moreover, density functional theory calculation also showed that the precise interface modification of MoS2/NiS heterostructure exhibited more occupations at the Fermi level, which improved the electrical conductivity. Additionally, the MoS2/NiS catalysts achieved a moderately lower hydrogen adsorption energy (ΔGH*), indicating that it had better catalytic hydrogen evolution performance. This work can be extended to design other catalytic materials and for understanding reactions in the fields of energy conversion through theoretical calculations. [ABSTRACT FROM AUTHOR]

Objective: Head and neck cancer is one of the most common cancer types worldwide. MicroRNAs play a vital regulatory role in the occurrence and development of cancer. The objective of this study is to explore the mechanism of miR-125a-5p in the proliferation, migration and apoptosis of head and neck cancer cells and define its target genes.Methods: The effects of miR-125a-5p on head and neck cancer cells proliferation, cell cycle distribution, apoptosis and migration were evaluated by colony formation, BrdU assay, flow cytometry and transwell assays. The potential target gene of miR-125a-5p was determined by luciferase activity assay and western blot analysis.Results: In this study, overexpression of miR-125a-5p significantly inhibited the proliferation of head and neck cancer cells, whereas inhibition of miR-125a-5p enhanced their proliferation. BrdU assay and flow cytometry revealed that miR-125a-5p might inhibit the proliferation of cancer cells by causing cell cycle arrest. Cell apoptosis assay and Transwell assay indicated that miR-125a-5p induced cell apoptosis and inhibited cell migration of cancer cells. Other experiments confirmed that miR-125a-5p could significantly downregulate its expression by binding to ERBB3 to inhibit proliferation and ERBB3 could at least partially mediate the inhibition of miR-125a-5p on the proliferation of head and neck cancer cells.Conclusion: The findings of this study suggested that the miR-125a-5p/ERBB3 axis might play a role in the proliferation, regulation of cell cycle, migration and apoptosis of head and neck cancer cells, potentially offering a new target for treatments of head and neck cancers. [ABSTRACT FROM AUTHOR]

Transition metals are increasingly attracting interest in electrocatalysts for use in water decomposition due to their excellent catalytic activity and stability. Simultaneously, metal-organic frameworks with designable metal ion centers and organic ligands are the promising precursors for the one-step synthesis of metal encapsulated in carbon composites for alkaline hydrogen evolution reaction (HER). Herein, we report the successful construction of Co-CoO/ZnFe 2 O 4 encapsulated in carbon nanowires (Co-CoO/ZnFe 2 O 4 @CNWs) by annealing as-synthesized nanowire Co/Zn/Fe-MOF at 400 °C in N 2. This structure provides the rich defect sites and active centers, and the synergy of Co, CoO and ZnFe 2 O 4 lead to efficient hydrogen evolution when the composite is used as a catalytic electrode for HER in 1.0 M KOH. The catalyst shows a low initial overpotential (97 mV) and a small Tafel slope (138 mV dec−1), and the overpotential at 10 mA cm−2 is only 226 mV. In addition, this composite material exhibits excellent long-term durability even after 1000 cycles. It is expected that it is a potential alternative catalyst for rational utilization in the field of electrolytic water decomposition. [ABSTRACT FROM AUTHOR]

We report a facile one-pot solvothermal synthesis of NiPd alloy homogeneously encapsulated between reduced graphene oxide sheets and N-doped carbon layers (rGO@NiPd@NC) with sandwich structure. In this study, dopamine served as both carbon-nitrogen source and green reagent, which cannot only form N-doped carbon layers encasing metal nanoparticles through high-temperature roasting but also co-reduce metal ions to form NiPd alloy. The rGO@NiPd@NC nanocomposite exhibits enhanced hydrogen evolution reaction (HER) activity with a small overpotential of 56 mV at 10 mA cm−2 and a Tafel slope approaching 33 mV dec−1 in acidic aqueous media, which are similar to the HER activity of commercial Pt/C catalyst (52 mV at j = 10 mA cm−2; Tafel slope, 31 mV dec−1). Additionally, the electrocatalyst which reveals excellent electrochemical stability is reflected in that the polarization curve shows negligible difference after 1000 cycles and the current density only slightly decreases within 20 h test, providing more possibilities for practical application in the future. [ABSTRACT FROM AUTHOR]

Bifunctional Pt-Ru/zeolite Y catalysts were prepared by ethylene glycol reduction (EGR) method, with 3 wt% of Pt and various ratios of Ru. The performance of catalysts was investigated for hydrogenation of levulinic acid (LA) to produce gamma-valerolactone (GVL). Catalysts were thermally treated in presence of NaOH and re-evaluated. The results showed that the thermal treatment contributed to adjustment of bifunctional Pt-Rux/Y acidity and further improved hydrogenation activity conversion of LA up to 100% and yield of GVL up to 97.99%. It also preserved the crystal structure of zeolite and showed better thermal stability as compared to Pt/Y and Ru/Y catalysts. • Pt-Rux/zeolite Y catalyst was achieved using the ethylene glycol reduction method. • Subsequent alkaline treatment allowed activation of Pt sites and adjusted zeolite acidity. • Treated Pt-Ru/zeolite catalysts showed the highest product and selectivity to GVL. • The treated catalysts showed better thermal stability and preserved the structure of the zeolite. [ABSTRACT FROM AUTHOR]

High-quality mesoporous or hollow ZnS@g-C 3 N 4 /TiO 2 nanospheres were fabricated successfully via structure regulation strategy for efficient photocatalytic H 2 production under visible-light irradiation. The entire process was started with the construction of solid ZnS@g-C 3 N 4 /TiO 2 (S-ZnS@g-C 3 N 4 /TiO 2 ) nanospheres. Then, via TiO 2 nanosheets (NSs) in situ growth or Ostwald ripening treatment, S-ZnS@g-C 3 N 4 /TiO 2 could be converted into mesoporous or hollow ZnS@g-C 3 N 4 /TiO 2 nanospheres automatically. The obtained porous ZnS@g-C 3 N 4 /TiO 2 nanospheres were featured of regular shape, high porosity, large specific surface area and adjustable g-C 3 N 4 content. In mesoporous ZnS@g-C 3 N 4 /TiO 2 (M-ZnS-g-C 3 N 4 /TiO 2 ) nanospheres, the specially constructed mesoporous served as channels for the access of reactants in heterogeneous catalysis. Besides, the electron-sink function of ZnS NPs and C–SO x –C sulfone bridges between ZnS and g-C 3 N 4 could improve visible-light H 2 production of M-ZnS-g-C 3 N 4 /TiO 2 significantly. Additionally, the prepared hollow ZnS@g-C 3 N 4 /TiO 2 (H-ZnS@g-C 3 N 4 /TiO 2 ) nanospheres showed a lower photocatalytic H 2 production than M-ZnS-g-C 3 N 4 /TiO 2 due to the decreased specific surface area. Compared with traditional g-C 3 N 4 wrapping method, the proposed structure regulation strategy is simple, effective and structural controllable. Finally, a possible photocatalytic mechanism for visible-light H 2 production by porous ZnS@g-C 3 N 4 /TiO 2 nanospheres was tentatively proposed. [ABSTRACT FROM AUTHOR]

A facial, one-step soft templating method to synthesize the hollow mesoporous g-C 3 N 4 spheres with high surface area and high porosity was developed, which taking advantage of both supramolecular assembly of cyanuric acid and melamine through hydrogen bonds and the structure-directing character of ionic liquid. The influence of solvent and ionic liquid content on the assemble behavior of the cyanuric acid-melamine complex is studied in detail, respectively. It is found that the as-prepared hollow g-C 3 N 4 spheres possess plenty of mesopores with a high surface area, which is related to the release of volatile domains and decomposition of ionic liquids. Moreover, as-prepared g-C 3 N 4 exhibit improved light absorption in visible ranges, faster separation rate of photogenerated hole-electron pairs than the bulk carbon nitride. Besides, the as-prepared hollow mesoporous carbon nitride exhibits almost 30 times higher than traditional g-C 3 N 4 which calcined by melamine for the photocatalytic hydrogen evolution reaction under visible light irradiation, which may be caused by the fact that the high surface area is beneficial for improving light absorption in visible ranges, and finally enhancing the H 2 evolution rate. This method paves new opportunities for designing other catalysts with high surface area. [ABSTRACT FROM AUTHOR]

Ag/AgCl/BiOCl three-component visible-light-driven photocatalysts were successfully fabricated using the reactable polyelectrolyte, poly(allylamine hydrochloride) as the template by a simple solvothermal method for the first time. The influence of Ag content on the formation of Ag/AgCl/BiOCl was systematically investigated. The samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), scanning electron microscope (SEM), N 2 gas sorption, electron spin resonance (ESR) and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS). The formation mechanism of the Ag/AgCl/BiOCl materials which was mainly based on the self-assembly of polyelectrolyte was proposed. In addition, the photocatalytic activity of the as-fabricated Ag/AgCl/BiOCl was evaluated by the degradation of rhodamine B (RhB) and tetracycline (TC) under visible light irradiation. Compared to pure BiOCl, Ag/AgCl and Ag/AgCl/BiOCl obtained by traditional one-step chemical bath method, as-fabricated Ag/AgCl/BiOCl materials displayed more superior photodegradation efficiency, which might be attributed to the surface plasmon resonance (SPR) effect of Ag nanoparticles. According to the results of radical trapping experiments and ESR measurement, it can be concluded that the photogenerated holes and superoxide radical are the predominant active species in the photocatalytic process. Furthermore, the photocatalytic mechanism has been proposed based on the characterizations and analysis. The as-prepared Ag/AgCl/BiOCl exhibited enhanced photocatalytic ability in the degradation of dyes and TC, suggesting its superiority in the future practical industries. This route preparing the Ag/AgCl/BiOCl materials with special structure inspires a new approach to prepare the visible light driven photocatalysts with novel morphologies and advanced properties in addressing environmental protection problems. [ABSTRACT FROM AUTHOR]

Coping with the gradually increasing worldwide energy and environmental issues, it is urgent to develop efficient, cheap and visible-light-driven photocatalysts for hydrogen production. Here, we present a facile way to synthesize bromine doped graphitic carbon nitride (CN-Br X ) with highly porous structure by using ionic liquid (1-butyl-3-vinylimidazolium bromide) as the Br source and soft-template for the first time, which applied in hydrogen evolution under visible light irradiation. A systematic study is conducted on the optimization in the doping amount. The results find that the as-fabricated CN-Br X photocatalysts possess a uniform porous network with thin walls due to the release of volatile domains and decomposition of ionic liquids. The highly porous structure with the large surface area (≤150 m 2 /g) benefits the exposure of active sites. Moreover, the bromine modification and porous structure can narrow the band gap, enhance the transportation capability of photogenerated electrons, improve the optical and conductive properties of CN, thus contribute to an outstanding H 2 evolution rate under visible light irradiation (120 μmol h −1 ), which is about 3.6 times higher than pure CN. This work provides a new insight for designing the novel g-C 3 N 4 based photocatalysts for hydrogen production, CO 2 conversion and environmental remediation. [ABSTRACT FROM AUTHOR]

In this work, we report a feasible approach to synthesize a ternary nanocomposites, Pt/lanthanum doped mesoporous zirconium oxide (Pt/La 2 O 3 -ZrO 2 ), via an effective two-step method. Ordered mesoporous La 2 O 3 -ZrO 2 composites were firstly fabricated with mesoporous silica KIT-6 as a hard template. Subsequently, uniform Pt nanoparticles encapsulated by 4 hydroxyl-terminated poly (amidoamine) (G4-OH PAMAM) dendrimers were deposited on the La 2 O 3 -ZrO 2 composites. The as-prepared samples were characterized by transmission electron microscope (TEM), N 2 adsorption–desorption isotherm analysis, energy dispersion X-ray analysis (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and temperature programmed reduction (H 2 -TPR). The average size of PtDENs was found to be 1.48 nm in diameter. Furthermore, the introduction of La could improve the structure of the supports which was confirmed by XRD and H 2 -TPR analysis. The reduction of p-nitrophenol to p-aminophenol by NaBH 4 was utilized to evaluate the catalytic performances of catalysts. Results indicated that the Pt/La 2 O 3 -ZrO 2 catalyst calcined in nitrogen at 550 °C exhibited the highest catalytic performance and still kept the high catalytic activity even after six cycles. This phenomenon suggests that synergistic effect among Pt-Zr-La could enhance the catalytic efficiency. Finally, reaction mechanism was proposed for the reduction of p-nitrophenol. [ABSTRACT FROM AUTHOR]

ZnO/Ag 2 O heterostructures have been successfully fabricated using ionic liquids (ILs) as templates by a simple photochemical route. The influence of the type of ionic liquid and synthetic method on the morphology of ZnO, as well as the photocatalytic activity for the degradation of Rhodamine B (RhB), tetracycline (TC) and ciprofloxacin (CIP) under ultraviolet and visible light irradiation was studied. The samples were characterized by XRD, SEM, TEM, PL and UV–vis DRS. The results established that the type of ionic liquid and synthetic method played an important role in the growth of ZnO nanoparticles. And as-fabricated ZnO/Ag 2 O materials exhibited self-assembled flower-like architecture whose size was about 3 μm. Moreover, as-prepared ZnO/Ag 2 O exhibited the enhanced photocatalytic activity than ZnO sample, which may be due to the special structure, heterojunction, enhanced adsorption capability of dye, the improved separation rate of photogenerated electron–hole pairs. According to the results of radical trapping experiments, it can be found that •OH and h + were the main active species for the photocatalytic degradation of RhB. It is valuable to develop this facile route preparing the highly dispersive flower-like ZnO/Ag 2 O materials, which can be beneficial for environmental protection. [ABSTRACT FROM AUTHOR]

A novel binary-metal-oxide-coated hollow microspheres-titanium dioxide-zirconium dioxide-coated Au nanocatalyst was prepared via a facile hydrothermal synthesis method. SEM, TEM, EDX, FTIR, XRD, UV–vis and XPS analyses were employed to characterize the composition, structure, and morphology of ZrO 2 –TiO 2 hollow spheres. The size of Au nanoparticles was found to be 3–5 nm in diameter before being immobilized on the aforementioned mesoporous ZrO 2 –TiO 2 layer and used as catalysts in the reduction of 4-nitrophenol to 4-aminophenol by NaBH 4 . Compared with TiO 2 /Au and ZrO 2 /Au, ZrO 2 –TiO 2 /Au NPs showed a higher catalytic activity because of due to mixed oxide synergistic effect. Besides, the sample gets the highest thermal stability and reactivity at 550 °C, after calcining the hollow ZT/Au NPs at 550 °C, 300 °C and room temperature, respectively. Finally, a possible reaction mechanism was also proposed to explain the reduction of 4-nitrophenol to 4-aminophenol over ZrO 2 –TiO 2 /Au catalyst. [ABSTRACT FROM AUTHOR]

A novel hierarchical TiO 2 @Pt@mSiO 2 hollow nanocatalyst with enhanced thermal stability has been synthesized successfully. The formation procedure involves a facile synthesis of SiO 2 @TiO 2 @Pt nanospheres and a subsequent solvothermal process. During the hydrothermal process, original TiO 2 layer was transformed into a hierarchical nanostructure and, meanwhile, etch-released silica species redeposited on the surface of the in-situ grown TiO 2 nanoplatelets. In the catalytic system, the in-situ grown TiO 2 nanoplatelets were buried in the redeposited mSiO 2 layers and the Pt NPs dispersed uniformly between TiO 2 nanoplatelets and mSiO 2 layers. Importantly, the redeposited mSiO 2 layer provides a physical barrier to prevent Pt NPs from sintering up to 550 °C and the hierarchical TiO 2 nanostructure shows an obvious co-catalysis effect in the reduction of 4-NP. Besides, the mSiO 2 layer could also control the rapid crystallization process of TiO 2 nanoplatelets effectively. In the high temperature reaction of propane dehydrogenation, HHN exhibits a lower deactivation parameter, indicating the excellent thermal stability. [ABSTRACT FROM AUTHOR]

Here we present a facile method for the preparation of highly dispersive ZnO materials by using ionic liquid 1-methyl-3-[3′-(trimethoxysilyl) propyl] imidazolium chloride as the template. The influence of ionic liquid concentration and calcined atmosphere on the photoactivity is studied. The samples were characterized by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), scanning electron microscope (SEM), N 2 gas sorption and ultraviolet-visible diffuse reflectance spectroscopy. The results showed that the as-fabricated ZnO materials consisted of individual microrods with self-assembled bowknot-like architecture whose size was about 1 μm. The formation mechanism of the bowknot-like ZnO materials which is based on the self-assembly of ionic liquid is tentatively elucidated. Moreover, the ZnO-2.6N sample exhibited the higher activity for the photodegradation of MB than the photodegradation of MO and RhB. Furthermore, it was found that the ZnO materials calcined under air atmosphere showed the better photocatalytic activities than that of samples calcined under nitrogen atmosphere in the degradation of methylene blue (MB) under UV irradiation. And the special structure, surface area, adsorption capability of dye, the separation rate of photogenerated electron–hole pairs and band gap had effects on the photocatalytic activity of ZnO photocatalysts. O 2 − was the main active species for the photocatalytic degradation of MB. It is valuable to develop this facile route preparing the highly dispersive bowknot-like ZnO materials and the ZnO materials can be beneficial for environmental protection. [ABSTRACT FROM AUTHOR]

A novel strategy was described to construct Au-based yolk-shell SCVmS-Au nanocomposites (NCs), which combined the sol-gel template-assisted process for the assembly of hierarchical SCVmS NCs with modified CeO 2 /mSiO 2 as yolks/shells, and the unique deposition-precipitation (DP) process mediated with Au(en) 2 Cl 3 compounds for the synthesis of extremely stable supported Au nanoparticles (NPs). Characterization results indicated that the obtained SCVmS-Au NCs featured mesoporous silica shells, tunable interlayer voids, movable CeO 2 -modified cores and numerous sub-5 nm Au NPs. Notably, the Au(en) 2 Cl 3 was employed as gold precursors to chemically modify into the modulated yolk-shell structure through the DP process and the subsequent low-temperature hydrogen reduction induced the in-situ formation of abundant supported Au NPs, bestowing these metal NPs with ultrafine grain size and outstanding sinter-resistant properties that endured harsh thermal conditions up to 750 °C. Benefiting from the structural advantages and enhanced synergy of CeO 2 -Au/mSiO 2 -Au yolks/shells, the SCVmS-Au was demonstrated as markedly efficient catalysts with superior activity and reusability in catalyzing the reduction of 4-nitrophenol to 4-aminophenol, and its pristine morphology still maintained after eight recycling tests. [ABSTRACT FROM AUTHOR]

A facile strategy has been developed for the synthesis of H-TS-Au microspheres (MCs) with double-shelled hollow architecture and sub–5 nm Au nanoparticles (Au NPs). The synthetic procedure involves the successive sol-gel template-assisted method for the preparation of uniform hierarchical hollow-in-hollow H-TS MCs with TiO 2 /mSiO 2 as yolks/shells, and the unique deposition-precipitation method mediated with Au(en) 2 Cl 3 precursors for the in-situ construction of extremely stable Au NPs under a low-temperature hydrogen reduction. The synthesized H-TS-Au MCs were characterized by TEM, SEM, FTIR, XRD, BET and UV–vis absorption spectra. Catalytic activity of H-TS-Au was evaluated using the reduction of 4-nitrophenol (4-NP) into 4-aminophenol (4-AP) by NaBH 4 . Results established that H-TS-Au MCs possessed a large-size double-shelled architecture with high structural integrity and robustness,which can effectively confine numerous tiny Au NPs and restrict them from sintering aggregation even up to further calcination at 800 °C. Owing to the advantageous structural configuration and the synergistic effect of TiO 2 /mSiO 2 double shells, the H-TS-Au MCs were demonstrated to exhibit a remarkable catalytic activity and stability, and preserve the intact morphology after 6 repeating reduction of 4-NP. [ABSTRACT FROM AUTHOR]

The design and development of flexible and free-standing molybdenum (Mo)-based composite nanomaterials have aroused intensive attention in the fields of electrocatalysis, energy storage, and wearable electronics. In this study, novel nanocomposite membranes constructed with Mo-based compound nanocrystals loaded carbon nanofibers (CNFs) were successfully generated by a combination of electrospinning molybdenum acetylacetone-contained polyacrylonitrile (PAN) solution and subsequent annealing process from 580 to 900 ºC. The relationship and mechanisms between the generation of different types of Mo-based nanocrystals and the annealing temperature were systematically explored. It was found that MoO 2 nanocrystals were formed when the annealing temperature was 580 °C. With the temperature increasing, Mo 2 N nanocrystals began to form due to the reaction between the formed MoO 2 and the N atoms in the PAN macromolecules. At higher temperature like 669 °C, Mo 2 C nanocrystals started to form due to the reaction between Mo 2 N and C atoms in the carbonized PAN macromolecules, and single-phase Mo 2 C nanocrystals were produced in CNFs at 900 ºC. Then, a series of flexible CNF-based nanocomposite membranes embedded with various different types of Mo-based compound nanocrystals were generated by effectively controlling the annealing temperature, which were all utilized as anodes for the construction of lithium-ion batteries. Electrochemical measurements showed that the anode materials annealed at 600 oC possessed the highest specific capacity, which were due to the high theoretical specific capacity of MoO 2 and significantly improved conductivity of Mo 2 N. Moreover, all the as-developed electrodes exhibited excellent cycling stability during the charge-discharge process. The present study provides a facile and broadly-applicable routine to tailor the component, structure, and electrochemical properties of Mo-based nanocrystals in CNFs, which finds huge application potential in the fields of various flexible electrochemical devices. • Mo-based compound nanocrystals loaded carbon nanofibrous membranes were created. • The formation mechanisms of different types of Mo-based nanocrystals were explored. • Tailing the annealing temperature could adjust the phase evolution of Mo-based Nanocrystals. • High performance Mo/C nanofibrous membranes were generated for the anode of LIBs. [ABSTRACT FROM AUTHOR]

A novel method has been developed for the preparation of highly active and thermally stable Au nanocatalysts, including a ZrO 2 -TiO 2 (hereafter referred to as ZT) mixed oxide layer, a moveable Hollow Fe 3 O 4 (hereafter referred to as HwFe 3 O 4 ) magnetic core and some Au NPs of 5–8 nm. This method involves the in situ reduction of Au NPs on the C/HwFe 3 O 4 nanospheres by using the C layer as the reducing agents. SEM, TEM, EDX, and XRD were employed to characterize the prepared samples. The results showed the ZT layer could increase the thermal stability and reactivity. The reduction of 4-nitrophenol (4-NP) into 4-aminophenol (4-AP) was employed as a model reaction to test catalytic performance in this work. The results showed the ZT/Au/C/HwFe 3 O 4 nanospheres calcined at 750 °C showed the highest catalytic activity, compared to the samples calcined at 550 °C and RT, respectively. Meanwhile, the sample (750 °C) still has certain of magnetism, suggesting the desired samples could be separated by magnet. Finally, the catalyst was reused for several cycles to reduce the nitrophenol. [ABSTRACT FROM AUTHOR]

[Display omitted] • Heterojunction with built-in electric field shows superior catalytic activity. • Self-driven system and induced effect synergistically boost carrier separation. • Induced effect promotes the migration of electrons to the surface of MOFs. • Self-driven system ensures rapid enrichment of e- in the conduction band of MOFs. • The recombination of photogenerated carriers is effectively suppressed. The construction of heterojunctions with a rapid space charge separation mechanism is an effective means to improve the photocatalytic activity. In this work, QDs/NH 2 -MIL-101(Fe)-AP photocatalyst equipped with built-in electric field was rationally prepared by a molecular modification strategy. Electron-withdrawing effect of the pyridine ring facilitates the directional transfer of electrons from the internal part of NH 2 -MIL-101(Fe) to the heterojunction interface. Meanwhile, the electron self-driven effect incidental to the suitable conduction band positions of QDs and NH 2 -MIL-101(Fe)-AP, and the co-driving effect of electron transfer exerted by hydrogen bonding accelerate the electron enrichment in the conduction band of NH 2 -MIL-101(Fe)-AP. The photocatalytic hydrogen evolution results showed that QDs/NH 2 -MIL-101(Fe)-AP reached an optimum rate of 2991.0 µmol h−1 g−1. Moreover, fluorescence and electrochemical tests revealed that the significant increase in photocatalytic activity is attributed to the efficient spatial separation of the photoinduced charge carriers. [ABSTRACT FROM AUTHOR]

In this study, a series of PtSnK/ZSM-5 catalysts for propane dehydrogenation were prepared by changing the impregnation sequence of platinum and tin precursors (co-impregnation and successive impregnation). To investigate the influence of impregnation strategy on the catalyst structure and the reaction performance, the prepared samples were studied by several techniques, including XRD, nitrogen adsorption, ICP, TEM, NH-TPD, FT-IR, hydrogen chemisorption, H-TPR, and TPO. It was found that the prepared sample with co-impregnation method showed the highest reaction stability and selectivity when comparing with the ones prepared by the sequential impregnation. As for the co-impregnated catalyst, high metal dispersion, strong interaction of Pt with Sn oxide together with the decreased catalyst acidity were all responsible for the improved reaction properties and better catalytic capacity to resist the coke. Nevertheless, over the sequentially impregnated catalysts, the increased catalyst acidity and the relatively easy reduction of tin species were found when the Pt components were deposited first. Furthermore, the successive impregnation with inverse sequence led to the wide metallic distribution and the restricted transformation of the active sites. All of these factors were disadvantageous to the reaction to be carried out. Finally, a model for the influences of impregnation sequence was proposed based on the obtained results. [ABSTRACT FROM AUTHOR]

Zinc containing ZSM-5 zeolite was hydrothermally synthesized and then was used as support for platinum catalyst in propane dehydrogenation. To investigate the location and the influence of Zn concentration on the catalyst structure and the reaction performance, the prepared samples were studied by several techniques, including XRD, nitrogen adsorption, SEM, NH 3 -TPD, TEM, hydrogen chemisorption and H 2 -TPR. It was found that some parts of zinc species could be incorporated into the framework of ZSM-5 zeolite and the introduction of zinc at the synthesis resulted in the formation of the agglomerated crystal rods, which in consequence increased the specific surface area. Additionally, the presence of zinc poisoned the strong acidity of the zeolite evidently. Compared with the Zn-free support, the substitution of Zn in the support strengthened the interaction of platinum with support and increased the platinum dispersion effectively. In this case, relatively homogeneous distribution of metallic particles was found due to the “geometric effect” of Zn. Unlike the impregnation method, the substitution of Zn was more beneficial to reflect the modification effect of the promoter to the metal phase and support acidity. In our experiments, the PtNa/Zn(1.0%)-ZSM-5 catalyst exhibited the highest reaction activity and stability. Nevertheless, with the continuous increase of Zn amount, the metal character had been changed. The formation of PtZn alloy resulted in the loss of catalytic activity and stability, while had a promoting effect for the reaction selectivity. [ABSTRACT FROM AUTHOR]

Ce-doped mesoporous γ-alumina with different contents of Ce was prepared by the sol-gel synthesis method and applied for the synthesis of propane dehydrogenation catalysts. To investigate the influence of different Ce contents on the properties of the supports, the prepared samples were characterized by several techniques, such as XRD, N-physisorption, TEM, XPS, NH-TPD, and hydrogen chemisorption. The results showed that, by the incorporation of Ce, the pore structure was changed, the acid content was decreased, and the properties of the metallic Pt particles were promoted significantly. Based on these effects, the coke deposits on the active center were suppressed and even migrated to the external surface of the support. As expected, when the content of Ce is suitable (0.6 wt%), the catalytic performance of propane dehydrogenation and the stability of the catalyst were highly promoted. [ABSTRACT FROM AUTHOR]

Optically active polyacetylene@CdTe Quantum Dots (HPA@CdTe and RPA@CdTe) composites have been prepared based on the surface modification of CdTe quantum dots (QDs). The as-prepared HPA@CdTe and RPA@CdTe were characterized by Fourier-transform infrared spectroscopy, UV-Vis absorption spectra, X-ray diffraction, thermogravimetric analysis, transmission electron microscopy and scanning electron microscopy. The infrared emissivity of HPA@CdTe and RPA@CdTe was also investigated. The results indicate that the polyacetylenes were successfully grafted onto the surfaces of the CdTe QDs without destroying the original crystalline structure of the CdTe QDs. Moreover, the infrared emissivity values of the HPA@CdTe and RPA@CdTe composites were reduced to 0.392 and 0.454, which possess much lower infrared emissivity values than those of the pure polymers and nanoparticles. The results are attributed to interfacial interactions between the organic and inorganic components. Furthermore, the helical conformation may also reduce the infrared emissivity due to the more ordered stereo structure and regular secondary structure. [ABSTRACT FROM AUTHOR]