Ni2P/Fe-HAP催化剂的表征及其苯酚加氢表面作用机理

以低品级羟基磷灰石(HAP)为原料,通过离子交换法合成载体Fe-HAP,然后用浸渍法制备出负载型Ni_2P/HAP和Ni_2P/Fe-HAP催化剂。通过BET、SEM、XRD、FTIR和TG等手段对催化剂进行了表征。Fe~(3+)的引入极大地提高了载体的比表面积,Ni_2P分散在Fe-HAP表面,热稳定性较好。以苯酚加氢制备环己酮为反应体系,在反应温度为150℃、压力为0.5 MPa、时间为3.5 h的条件下,对比了Ni_2P/HAP和Ni_2P/Fe-HAP催化剂的催化性能。结果发现,Ni_2P/Fe-HAP催化剂对苯酚的转化率为65.73%,环己酮选择性为85.47%,催化性能相对良好。     

固体碱羟基磷灰石催化苯酚酯化合成乙酸苯酯

以沉淀法制备了固体碱羟基磷灰石(HAP),采用XRD对其进行了表征,并探讨了工艺条件对HAP催化乙酸酐与苯酚酯化合成乙酸苯酯反应的的影响。实验结果表明,当固体碱催化剂HAP的用量为4%(以原料总重量计),原料乙酸酐与苯酚的摩尔比1.05∶1.00,反应温度140～150℃,反应时间3h时,乙酸苯酯的收率达93.1%,且催化剂的稳定性良好     

水滑石催化剂及催化氧化反应性能

水滑石作为一种很有潜力的无机功能材料,近年来在催化领域得到广泛应用.对近年来水滑石催化剂材料的催化氧化反应性能,特别是以层板过渡金属为催化活性组分催化氧化醇、酚和烷烃等化合物的反应;以插层阴离子作为催化活性组分催化烯烃和酯的环氧化反应;负载纳米金属颗粒作为催化活性组分催化氧化醇、烷烃和糠醛等化合物的反应等方面的研究进展...     

氧化物负载型亚纳米金属催化剂的制备及其在有机催化中的应用

近几年来，亚纳米金属催化剂(单原子催化剂和团簇催化剂)由于具有高的催化活性和金属原子利用率，在各个领域里具有重要研究意义，尤其是在有机催化反应中表现出优异的催化性能。氧化物因其具有丰富的缺陷位点、表面酸碱位点和高温稳定性等多种优势，作为负载型亚纳米金属催化剂的载体材料。主要综述了氧化物载体负载型亚纳米金属催化剂的几种合成方法及其在氧化反应、加氢反应及偶联反应等有机催化中的应用。     

羟基磷灰石纳米棒的可控制备及其催化一氧化碳氧化性能

采用简单的一步水热法,以赖氨酸为沉淀剂,通过改变赖氨酸浓度,合成不同尺寸的羟基磷灰石(HAP)纳米棒,负载质量分数3%Ag制备Ag/HAP催化剂。利用Ag与HAP之间的强相互作用将Ag纳米粒子分散在HAP载体表面,使其具有较好的催化活性。活性测试发现,赖氨酸浓度为0. 20 mol·L~(-1)时,制备的Ag/HAP催化剂催化性能最好,在空速为60 000 mL·(g·h)~(-1)条件下,CO的完全转化温度为190℃。XRD和SEM表征结果表明,赖氨酸浓度对Ag/HAP催化剂的结构和性能影响较大。UV-vis、H_2-TPR和XPS测试结果表明,活性组分Ag主要以Ag~0和Ag~+的形式存在于HAP载体上,其中Ag0作为主要催化活性中心,使Ag/HAP催化剂在CO氧化反应中保持较高的活性。     

碳材料用于低温选择性催化还原脱硝的研究进展

选择性催化还原技术是目前消除NOx的主流技术。碳材料作为自然界广泛存在的一种材料,具有比表面积大、化学稳定性好、结构可调控和表面可改性等优点,广泛应用于低温选择性催化还原反应。综述不同类型碳材料包括活性炭、活性炭纤维、碳纳米管、石墨烯和多孔碳在低温选择性催化还原中的应用,介绍碳材料作为活性组分和催化剂载体的使用情况,讨论表面化学改性对催化NOx性能的影响,阐述碳材料在加快反应速率和提升催化剂抗硫中毒方面的独特性能,并展望碳材料作为新型载体材料在低温选择性催化还原中的应用前景。     

负载NHC-Pd配合物催化Suzuki偶联反应的研究进展

钯催化的Suzuki偶联反应作为有效的构建碳-碳键的方法,在天然产物、药物全合成和有机合成工业中被广泛应用。而目前广泛应用的含钯均相催化剂尽管反应活性高,但昂贵钯金属盐或配合物不易回收,痕量残留于目标产品或者废液中,导致目标产品重金属污染和环境污染等弊端,极大地增加了该反应的成本和降低了产品的安全性,因此期望以易回收使用、低钯浸出的异相催化剂来实现对该反应的高效绿色催化。氮杂环卡宾钯配合物（NHC-Pd）在催化Suzuki偶联反应中具有反应活性高、稳定好等优点常被用作异相催化剂的催化中心。该文从异相催化剂的载体材料如高分子材料、多孔硅材料、碳基材料、金属-有机框架及磁性纳米粒子等出发,综述了近年来NHC-Pd在异相催化Suzuki偶联反应中的最新研究进展,对于今后该研究方向的开展具有指导意义。     

羟基磷灰石的合成及应用研究进展

羟基磷灰石(HAP)在替代性骨材料、骨组织工程等领域被广泛应用，同时也在抗菌、药物传输载体、吸附、催化、柔性耐火材料等生物医学、功能复合材料领域具有广泛应用前景。本文介绍了5种不同的HAP合成方法，可以制备出不同结构的HAP,以满足不同的应用需求。全面了解HAP的合成方法、结构特点和应用研究现状，有助于在HAP的功能拓展研究中，制定合理的研究方案，对其他类似的材料开发和应用研究也具有借鉴意义。     

生物质炭基材料在有机催化转化中的应用

近年来,生物质因具有富碳可再生、储量丰富、环境友好、价格低廉等特点被作为原料广泛应用于制备生物质炭基材料。本文综述了以生物质为原料衍生炭基材料作为催化剂在有机转化反应中的相关研究进展,重点介绍了杂原子掺杂、金属杂化策略所制备炭基催化材料在液相催化加氢、氧化、偶联等有机转化反应中的催化性能,进而阐明了炭基催化剂与催化活性之间的构效关系。最后,本文总结了生物质炭基催化剂在有机催化反应中的优势,指出了目前生物质衍生炭基催化剂材料合成和有机转化研究领域面临的挑战,并对此领域的未来发展趋势进行了分析与展望。     

非均相金属钯配体催化剂的研究进展

Suzuki-Miyaura反应是一类具有工业化应用前景的C-C键合成反应。反应多数是在均相金属钯配体催化剂催化下完成。均相催化具有催化效率高、产品选择性好等优点,但催化剂回收困难,增加了反应成本,限制了其应用。非均相金属钯配体催化剂是将均相金属钯配体催化剂固载到载体上,使其在不影响反应活性和选择性的同时,实现循环使用,已成为Suzuki-Miyau-ra反应的研究热点。对几年来以有序介孔材料MCM-41和SBA-15、无机载体SiO2和Al2O3、聚苯乙烯和聚乙二醇等合成材料以及天然高分子材料为载体,制备非均相金属钯配体催化剂的方法及其催化性能进行了综述。     

羟基磷灰石的焙烧条件对酯化合成乙酸苯酯的影响

考察了羟基磷灰石(HAP)的焙烧条件对乙酸酐与苯酚酯化合成乙酸苯酯反应的影响,并采用X-射线粉末衍射、N2吸附和扫描电镜对催化剂进行了表征。结果表明,焙烧条件通过影响HAP晶格中OH-的脱除和晶体结构的稳定性来改变表面的碱性,进而影响催化活性。最佳焙烧条件为:焙烧温度900℃、焙烧时间4h,在此条件下,乙酸苯酯收率达95.5%。     

Mineralization of hydroxyapatite on a polymer substrate in a solution supersaturated by polyelectrolyte

In this article, a new method to construct composites of hydroxyapatite (HAP) and polymer material is introduced. A previously developed method for mineralization of CaCO₃ on a polymer substrate was applied to HAP. A solution that contained Ca²⁺, PO₄^3–, and OH‐ ions was supersaturated with polyacrylic acid (PAA) that, at the same time, formed a polymer complex with the substrate, a polyvinyl alcohol (PVA) film, at the substrate surface. In this thin surface layer, nucleation of HAP took place. Subsequently, the disklike domains of HAP that were generated spread until they covered the PVA film surface. By regulating the pH of the supersaturated solution at around 7.4, the domain size decreased and the quantity of deposited material increased. Approximately 20 mg of HAP coating was obtained on a PVA film of 1 cm radius when the film was soaked in single 200 mL batch of the supersaturated solution for 21 days. The junction between HAP layer and PVA substrate film was found to be very firm. When a crosslinked PVA/PAA was used as the substrate, the film swelled in the supersaturated solution to form a hydrogel. Then mineralization took place within the gel, and a transparent monolithic composite of HAP and the polymer network was obtained. In 13 days, the weight increase was 29 mg, which corresponded to a 71 wt % HAP mineralization ratio of the composite. By changing crosslinking degree and HAP mineralization ratio, the flexibility of composite will be controlled in a wide range. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1465–1470, 2006     

The effect of lignin on the structure and characteristics of composite coatings electrodeposited on titanium

Composite coatings based on lignin, obtained by electrophoretic deposition (EPD) on titanium, were investigated. The aim of this work was to produce hydroxyapatite/lignin (HAP/Lig) coatings on titanium and to investigate the effect of the lignin concentration on microstructure, morphology, phase composition, thermal behavior and cytotoxicity of the HAP/Lig coatings. An organosolv lignin was used for the production of the composite coatings studied in this research. The properties of HAP/Lig coatings were characterized using X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FT-IR) and X-ray photoelectron spectroscopy (XPS), as well as the MTT test of cytotoxicity. The results showed that higher lignin concentrations protected the HAP lattice during sintering, thereby improving the stability of the HAP/Lig coatings. The cell survival of peripheral blood mononuclear cells (PBMC) after proliferation indicates that the HAP/Lig coating with 1 wt% Lig electrodeposited on titanium was non-toxic with significant promise as a potential bone-repair material.     

Transparent Hydroxyapatite Ceramics through Gelcasting and Low-Temperature Sintering

Transparent hydroxyapatite (HAP) was prepared by sintering gel-cast powder compacts at 1000°C for 2 h; the resultant HAP material was studied using X-ray diffractometry, transmission electron microscopy, scanning electron microscopy, and microhardness measurement. Nanoscale HAP crystallites were prepared using a precipitation method that involved calcium nitrate and ammonium dihydrogen orthophosphate solutions; the preparation was conducted at a temperature of 0°C. The precipitate was gel-cast and sintered at 1000°C in the form of a transparent ceramic that had a uniform grain size of 250 μm. The maximum Vickers microhardness obtained for a sample sintered at 1000°C was 6.57 GPa. The sintering behavior of gel-cast samples prepared from high-temperature-precipitated HAP was compared with that of material prepared at 0°C.     

羟基磷灰石对水溶液中锌离子的吸附动力学研究

以废弃的鸡蛋壳为原料,制备了碳羟基磷灰石,用红外光谱对其结构进行了表征。将得到的碳羟基磷灰石进行水溶液中锌离子的吸附,考察了吸附过程的动力学,结果表明,碳羟基磷灰石对水溶液中锌离子的吸附符合二级反应动力学方程：1/ρR=0.0536t＋1.0992,相关系数R=0.99724,其拟合度比较好。     

Novel interconnected nanochannel hydroxyapatite ceramics: synthesis,microstructure, and permeability

Uniform interconnected micro/nanoporous ceramics with good mechanical properties hold universal applications in biomedical and engineering fields. Herein, using hydroxyapatite (HAP) microtubes as the raw material instead of traditional particles, a novel interconnected nanochannel hydroxyapatite ceramic was fabricated successfully through one-step microwave sintering method without the addition of pore generators. The tubular structure of the HAP microtubes remains even after microwave sintering, which endows the ceramic with uniform interconnected nanochannels and 3-D porous structure. The HAP microtube nanochannel ceramic has a narrow pore size distribution from 400 nm to 600 nm, and exhibits well permeability, high adsorption/desorption ability. The porosity is about 30%, the HAP microtube nanochannel ceramic can be totally dyed by methylene blue within several minutes, and the blue dye can be desorbed completely in 45 min by ultrasonic vibration. In addition, due to the one-dimensional structure of the HAP microtubes, the HAP microtube nanochannel ceramic has smaller shrinkage, bigger porosity, and better toughness than the control sample fabricated by nanoparticles. Base on the uniform interconnected nanochannel structure, well permeability, high adsorption/desorption ability, the HAP microtube nanochannel ceramic fabricated here may be a promising candidate for many applications in biomedical engineering, environmental engineering, and energy engineering.     

电泳沉积羟基磷灰石生物陶瓷涂层的研究进展

羟基磷灰石(hydroxyapatite，HAP)生物陶瓷涂层被认为是目前最好的用于替代人体硬组织的一种生物医用材料。电泳沉积是一种全新的涂层制备方法，它可以解决传统HAP生物陶瓷涂层制备工艺上的各种不足。文中综合介绍了国内外有关电泳沉积HAP生物陶瓷涂层的研究报道，概述了电泳沉积的工艺流程和工艺参数，并对各种影响因素全面地进行了详细的探讨，进而提出了相应的设想和展望。     

Fluorescent hydroxyapatite‐loaded biodegradable polymer nanoparticles with folate decoration for targeted imaging

The preparation of the luminescent hydroxyapatite (HAP)‐loaded biocompatible nanoparticles (NPs) for targeted imaging of cancer cells is described. Currently, cellular imaging using fluorescent probes is an important technique for the early diagnosis of cancer. Compared with the quantum dots, luminescent HAP is a new fluorescent material with many advantages such as low toxicity, biocompatibility, thermal stability, resistance to erosion, and low prices. Thus, luminescent HAP has enormous potential to be used as biological fluorescent probes. However, luminescent HAP is water‐insoluble, low sensitivity, which limit its application in the field of cellular imaging. Surface modification of NPs with targeting molecule was carried out to achieve its target function. Thus, novel fluorescent NPs with low toxicity, high sensitivity, and good photostability were prepared to be used for targeted imaging of cancer cells. This study initially explored the applications of luminescent HAP in the field of targeted cellular imaging. This NPs platform will be a promising tool for molecular imaging and medical diagnostics, especially the detection of cancer at its early stage. © 2013 American Institute of Chemical Engineers AIChE J, 59: 4494–4501, 2013