A series of aluminum phosphate catalysts (xP-Al-O-T) with varying P/Al molar ratios and calcination temperatures were prepared via solvent evaporation self-assembly. The physicochemical properties of the prepared xP-Al-O-T catalysts were investigated using XRD, FTIR, Py-FTIR, nitrogen adsorption–desorption, and NH3-TPD. Results indicate that the xP-Al-O-T samples exist in crystalline form, with a predominantly weak Lewis acid surface. The performance of the catalysts in the formaldehyde–glycol acetalization reaction for 1,3-dioxolane synthesis was investigated. The effects of P/Al molar ratio and calcination temperature on catalyst activity were examined. The effects of reaction temperature, reactant molar ratio, and space velocity on catalytic performance were systematically investigated. Under the optimized conditions—a P/Al molar ratio of 1.50, calcination temperature of 550 °C, reaction temperature of 150 °C, reactant molar ratio of 1.1, and space velocity of 1 mL g⁻1 h⁻1—the conversion of ethylene glycol reached 95.52

Citral, a valuable natural fragrance, suffers from chemical instability that limits its industrial application. Acetalization with 1,2-propanediol offers an effective stabilization route. Herein, we report a series of Al-P(x)-O solid acid catalysts with tunable P/Al molar ratios, synthesized via a PEG-20000-assisted one-pot method. Comprehensive characterization (XRD, FT-IR, XPS, BET, SEM, NH3-TPD, and Py-IR) reveals that the P/Al molar ratio governs a fundamental shift in acid-type distribution from purely Lewis acidity to a synergistic Lewis-Brønsted bifunctional system. The optimized Al-P(1.20)-O catalyst achieves 64.6

Solketal is an important chemical product with widespread applications, and the raw materials glycerol and acetone are inexpensive, making it highly economically viable. The glycerol-acetone condensation reaction is a typical acid-catalyzed reaction. Traditional homogeneous acidic catalysts cause significant environmental pollution and are difficult to recover. Herein, PEG-800 was used as an additive, and a one-pot process was employed to prepare a series of aluminum phosphate catalysts (xP-Al-O) with different P/Al molar ratios. The physical and chemical properties of the prepared xP-Al-O catalysts were thoroughly investigated using XRD, FTIR, SEM, Py-FTIR, BET, and NH3 (CO2)-TPD methods. The results indicated that different P/Al molar ratios indeed affect the catalyst structure, and all prepared xP-Al-O samples exist in the form of amorphous aluminum phosphate, with weak acidic sites dominating the surface. The prepared catalysts were investigated for their catalytic behavior in the acetalization reaction of glycerol and acetone. The 1.1P-Al-O catalyst exhibited the highest acetone glycerol acetal yield and demonstrated good catalytic stability.

A series of aluminophosphate catalysts (xP-Al-O-T) with various P/Al molar ratios and calcination temperatures were prepared through a one-pot reaction with F127. The physical and chemical properties of the prepared xP-Al-O-T catalysts were thoroughly investigated using methods such as XRD, FTIR, Py-FTIR, low-temperature nitrogen adsorption–desorption, and NH₃-TPD. The results showed that the prepared xP-Al-O-T samples existed in the amorphous form and weak Lewis acidic sites on the surfaces were predominant. The prepared catalysts were investigated for their catalytic behaviors in gas-phase etherification of diethylene glycol monomethyl ether (DEGME) with dimethyl carbonate (DMC) to produce diethylene glycol dimethyl ether (DEGDME), which is regarded as a green synthetic route. The effects of different P/Al molar ratios and calcination temperatures on the catalyst performance were studied. All the tested catalysts exhibited 100

SBA-15-supported Al2O3-P2O5 with 10 wt

P2O5 has been widely used as an acid-base catalyst for the O-methylation of catechol to guaiacol due to its suitable acid strength; however, its stability, which is a significant concern for industrial applications, has not seen significant breakthroughs. Herein, we developed a facile impregnation strategy to synthesize Ce promote P2O5 supported on mesoporous silica (CeP/SBA). The CeP/SBA-500 carbonized at 500 degrees C exhibited the highest catalytic activity with a catechol conversion of 71.5 %. The high activity stems from the addition of Ce, forming CePO4, which exhibits improved surface acidity compared to P2O5. Importantly, chemisorption and in situ infrared studies revealed that CePO4 shows stronger adsorption of catechol, which then rapidly converts to guaiacol. The CeP/SBA-500 exhibits excellent stability with no activity decrease after 10 h of continuous flow reaction, attributed to the absence of a decrease in CePO4 surface acidity.

g-C3N4 supported Pd nanotetrahedrons (Pd NTs@g-C3N4) are first prepared by an in-situ growth method with water-induced process. The unique Pd nanotetrahedrons with four (111) facets exposed have been prepared by simply varying the dosage of water without the other synthesis condition changed. The optimized Pd NTs@gC3N4 exhibits higher activity (TOF value: 51462 h-1) toward the hydrogenation of nitrobenzene with respect to the commercial Pd/C. The enhanced activity is attributed to the small size and tetrahedral shape with higher surface energy and more active surface. Most importantly, the Pd NTs@g-C3N4 still shows excellent activity and selectivity for nitrobenzene hydrogenation without obviously deactivation after ten cycles. In addition, the vertical and parallel adsorption behaviors of nitrobenzene molecules on Pd (111) surface are analyzed in detail using the density functional theory (DFT) method, and the interaction mechanism between nitrobenzene and palladium is studied by the charge density difference method.

The complex patterns of flexible copper microcircuits were fabricated through chemical growth welding of silver seeds at a low temperature, exhibiting good conductivity, flexibility and fatigue durability.

The O-methylation of catechol is an effective method for the industrial production of guaiacol used as an important chemical. However, the low catechol conversion and poor catalyst stability are the most critical issues that need to be addressed. Herein, the O-methylation of catechol with dimethyl carbonate was investigated over aluminophosphate (APO) catalysts, using a continuous-flow system to produce guaiacol. APO catalysts were synthesized with varying P/Al molar ratios and calcination temperatures to study their effects on catalytic performance for the reaction. The physico-chemical properties of the APO catalysts were thoroughly investigated using XRD, NH3-TPD, CO2-TPD, FTIR, and Py-FTIR. The P/Al molar ratio and catalyst calcination temperature significantly influenced the structure and texture, as well as the surface acid-base properties of APO. Both the medium acid and medium base sites were observed over APO catalysts, and the Lewis acid sites acted as the main active sites. The APO (P/Al = 0.7) exhibited the highest catalytic activity and excellent stability, due to the suitable medium acid-base pairs.

通过一步沉淀-蒸发法制备了具有不同P/Al摩尔比(x=1.00、1.05、1.10、1.15、1.20)的无定形介孔Al-xP-O催化剂.通过X射线衍射(XRD)、N2吸附-脱附、电感耦合等离子体原子发射光谱(ICP-AES)、NH3程序升温脱附(NH3-TPD)和CO2程序升温脱附(CO2-TPD)等手段对制备的Al-xP-O催化剂进行表征,考察了P/Al摩尔比对催化剂表面酸碱性及催化性能的影响.当P/Al摩尔比在1.00～1.10范围时,随P/Al摩尔比增加,催化剂弱酸性位点数量增加,中等强度碱性位点数量降低,邻苯二酚转化率提高,邻羟基苯乙醚选择性提高.当反应温度为270℃、空速为3.0mL/(gcat·h)、P/Al摩尔比为1.10时,催化性能最佳.200h稳定性测试中,邻羟基苯乙醚选择性始终保持在93.0％左右,反应后催化剂无明显积炭,表明该催化剂对邻苯二酚与乙醇气相合成邻羟基苯乙醚反应具有较高的稳定性和工业应用价值.

A series of Al-P-O catalysts (Al-xP-O) were prepared using a P123-assisted one-pot method at different P/Al molar ratios and used for O-methylation of catechol and methanol. The influences of the P/Al molar ratio and P123 addition on catalyst structure and surface acid-base characteristics were investigated in detail. Increasing the P/Al molar ratio more favored crystalline aluminophosphate. The P123-assisted Al3+ and PO43− are known to be stabilized through weak steric force so that the formation of crystalline aluminophosphate could be inhibited at higher P/Al molar ratios. The results showed that the prepared Al-P-O catalysts possessed appropriate weak acid and weak base sites, which was beneficial to the reaction of catechol and methanol. The Al-1.1P-O catalyst synthesized with the assistance of P123 exhibited superior catalytic performances, with 52.5% catechol conversion and higher guaiacol selectivity of 97.6%.

Guaiacol produced by O-methylation of catechol with methanol over solid catalysts is a green environmental synthesis route. In order to achieve high catalytic efficiency, it is quite necessary to employ low-cost catalysts with high activity and stability. Herein, series of aluminophosphate catalysts were synthesized by a simple precipitation route modified by Zr. The characterization results indicated that the prepared Al-P-Zr catalysts possessed appropriate weak acid and weak base sites, which were beneficial for the O-methylation of catechol with methanol. Different Zr amount and calcined temperature exerted a significant influence on physicochemical properties of the catalysts and catalytic performance. The Al-P-Zr catalysts containing Zr/Al molar ratio of 0.012 calcined under 400 °C showed the optimal catalytic activity and long-term stability for vapor-phase selective O-methylation of catechol with methanol.

The effect of a high magnetic field on the γ′ phase of Ni-based single crystal superalloy during directional solidification is investigated experimentally. The results clearly indicate that the magnetic field significantly reduces the γ′ phase size. Further, the quenching experiment is carried out, and the results found that the length of mushy zone is obviously decreased under a high magnetic field. Based on both experimental results and nucleation mechanism, it is found that the decrease of γ′ phase size should be attributed to the fact that a high magnetic field causes the increase of temperature gradient in front of solid/liquid interface and leads to the increase of undercooling of γ′ phase.

针对氧化还原条件下获得的铁金属化率为92.5％ 的还原钛精矿,研究了采用FeCl3溶液选择性浸出铁获取富钛料,考察浸出过程中各变量对铁浸出效果的影响,并对优化条件下获得的浸出液进行离子膜电解再生浸出剂.结果表明:控制液固体积质量比10:1,在搅拌速度400 r/min、浸出剂中Fe3+总量与还原矿料中金属铁总量的比值R=2.3、室温、浸出1 h条件下,铁浸出率为98％ 以上,获得T iO2品位为76.2％ 的富钛料;以阴离子交换膜作隔膜,浸出液与FeCl2溶液分别作阳极液和阴极液进行电解,浸出剂得到再生并获得金属铁.

A series of 30 wt%Ni/CexZr1-xO2 catalysts doped with Ru ranging from 0 to 5 wt% were prepared by one-pot hydrolysis of metal nitrates with ammonium carbonate for carbon dioxide methanation at low temperature range of 150-310 degrees C. The influences of Ce/Zr molar ratios and Ru contents on the physicochemical properties and catalytic activities of prepared catalysts were systematically investigated. The addition Ru can improve the Ni dispersion and the basicity of the yRu-30Ni/Ce0.9Zr0.1O2 catalysts surface. As a result, their low-temperature catalytic activity had been enhanced over these doped Ru promoted catalysts. The optimal catalyst was 3Ru-30Ni/Ce0.9Zr0.1O2 on which the CO2 conversion reached theoretical equilibrium value as high as 98.2% with the methane selectivity of 100% at a reaction temperature as low as 230 degrees C. Moreover, there was almost no deactivation for the 3Ru-30Ni/Ce0.9Zr0.1O2 catalyst during 300 h at 230 degrees C indicating excellent catalytic stability and coke resistence ability. It was also found that the low-temperature activity of 3Ru-30Ni/Ce0.9Zr0.1O2 catalyst prepared by one-pot hydrolysis method was much higher than the one prepared by impregnation method. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Herein, nanoscale metallic nanoparticle-incorporated ordered mesoporous carbon catalysts activated by nitrogen-doped graphene (NGr) were fabricated via an efficient multi-component co-assembly of a phenolic resin, nitrate, acetylacetone, the nitrogen-containing compound 1,10-phenanthroline, and Pluronic F127, followed by carbonization. The obtained well-dispersed nitrogen-doped graphene-activated transition metal nanocatalysts possess a 2-D hexagonally arranged pore structure with a high surface area (∼500 m2 g-1) and uniform pore size (∼4.0 nm) and show excellent activity for the selective hydrogenation-reduction of substituted nitroarenes to anilines in an environmentally friendly aqueous solution. The high catalytic performance and durability is attributed to the synergistic effects among the components, the unique structure of the nitrogen-doped graphene layer-coated metallic nanoparticles, and electronic activation of the doped nitrogen.

Apoptosis is a crucial event for the efficacy of anticancer drug. Caspase-3 plays a critical role in cell signaling pathways of apoptosis. The calixarene derivatives display high affinity for various kinds of biomolecules by host-guest recognition own to their unique cavity structure. The calixarene functionalized reduction of graphene oxide exhibits stronger molecular recognition ability and a higher electrochemical response to biomolecules than unmodified graphene oxide. In this work, caspase-3 recognizes and cleaves N-terminal blocked peptide containing tetra-peptide substrate Asp-Glu-Val-Asp. p-sulfonatocalix[6]arenes sodium modified graphene oxide (pSC(6)-rGO) recognizes exposed N-terminal amine group assembled on the electrode. Due to the large surface area to volume ratio of rGO, numerous electrochemical active methylene blues (MB) can be absorbed through host-guest recognition. As a result, sensitive caspase-3 detection was achieved with a low detection limit of 0.0167 pg/mL by this electrochemical signal amplification strategy. This approach was also applied to measure apoptosis in the practical cell samples and shows good performance. (C) 2018 Elsevier B.V. All rights reserved.

Cerium oxide-supported palladium catalysts (Pd/CeO2) prepared by a simple impregnation method exhibit exciting catalytic activity and high chemoselectivity for the solvent-free hydrogenation of a variety of substituted nitroarenes including the reducible functional groups to the corresponding aromatic amines under mild reaction conditions. Taking nitrobenzene as an example, the Pd/CeO2 catalyst can afford aniline yields of > 99% with turnover frequencies as high as 11 411 h(-1) and 69824 h(-1) at 40 degrees C and 100 degrees C, respectively. Pd2+ ion species exist as isolated single atoms with -Pd2+-O2--Ce4+ - linkages on the surface of PdxCe1-xO2-sigma solid solution and are found to be active sites for the selective hydrogenation of nitroarenes in the absence of solvent. The superior catalytic performance can be attributed to the cooperative effect between Pd2+ ions and unique surface sites of CeO2. A possible mechanism is proposed for the hydrogenation of nitroarenes with H-2 over the Pd/CeO2. The Pd/CeO2 catalyst can be recovered easily and reused for at least seven recycling reactions without loss of catalytic properties.

A series of xNiAl2O4/γ-Al2O3 composites with various Ni contents have been prepared via one-step partial hydrolysis of metal nitrate salts in the absence of surfactants and used for carbon dioxide reforming of methane. The characterization results demonstrated that the NiAl2O4/γ-Al2O3 materials possessed mesoporous structures of uniform pore sizes; and the Ni2+ ions were completely reacted with alumina to NiAl2O4 spinel in the matrices using N2 sorption, XRD, TEM, and XPS. The NiAl2O4/γ-Al2O3 materials exhibited excellent catalytic properties and superior long-term stability for carbon dioxide reforming of methane. The effects of Ni content on the intrinsic activities and the amounts of coke disposition of the xNiAl2O4/γ-Al2O3 catalysts were discussed in detail for the carbon dioxide reforming of methane. The results revealed that the Ni particle sizes did not affect the intrinsic activity of metallic Ni, but smaller Ni particles could reduce the rate of coke deposition.

Mesoporous NiAl2O4/MOx (M = La, Ce, Ca, Mg)–γ-Al2O3 composites through a one-pot partial hydrolysis method showed excellent catalytic performance for dry reforming of methane.