水滑石纳米材料特性及其在电化学生物传感器方面的应用

阐述了水滑石纳米材料结构和性能之间的关系及近年来水滑石纳米材料在电化学生物传感器方面应用的最新进展。重点介绍了水滑石纳米材料在吸附生物酶制备电化学传感器、水滑石纳米片固定生物酶制备电化学传感器、水滑石纳米片固定其它活性组分制备电化学传感器、水滑石自构筑电化学传感器等方面的应用。着重对水滑石纳米材料制备电化学传感器的机理和制备方法进行了系统概述。提出了水滑石纳米材料构筑电化学生物传感器应用研究的发展趋势：对水滑石纳米材料进行多层、多组分、微型化和阵列化等多样化设计,指出高选择性和高灵敏度检测是未来新型电化学生物传感器应用研究的主要发展方向。     

类水滑石材料在污染控制中的应用

层状双羟基金属复合氧化物结构和性质上的特殊性,使水滑石成为一种新型多功能无机材料,应用于多个领域。水滑石类材料也可作为吸附剂、催化剂载体和微粒乳化剂等有效地用于环境污染防治,在实际应用方面已取得一系列研究成果。作为一种新型的环境矿物材料,其在环境污染控制领域呈现出良好的研究价值和应用前景。     

Novel Ni–Al nanosheet catalyst with homogeneously embedded nickel nanoparticles for hydrogen-rich syngas production from biomass pyrolysis

In this work, an innovative porous Ni–Al nanosheet catalyst synthesized by a homogeneous precipitation method via urea hydrolysis is proposed for enhanced hydrogen-rich syngas production from catalytic pyrolysis of rice husk in a two-stage reactor system. The role of synthesis temperature in modulating the crystalline composition, particle size, metal dispersion as well as porous structure of resulting Ni–Al nanocomposite has been delineated. The results indicate that fine spherical NiO and metallic Ni⁰ nanoparticles are homogeneously embedded in amorphous Al₂O₃ matrix for all Ni–Al catalysts, which also have developed bimodal micro/mesoporous structure with high surface areas (513–948 m²/g). Catalytic tests show that these highly active catalysts exhibit almost ten times higher hydrogen production rate (7.74–17.39 mmol/g biomass) and H₂/CO molar ratio (1.96–2.74) than that in the absence of catalyst (0.56–1.64 mmol/g, 0.11–0.24) by tuning catalytic temperatures. The Ni–Al catalysts that with the presence of metallic Ni⁰ and developed porous structure exhibit higher catalytic activity and suppression of coke deposition through providing more active sites for catalytic cracking and reforming reactions, and rapid diffusion of intermediate products.     

Nickel-induced structure transformation in hydrocalumite for enhanced ammonia decomposition

Modifying the material structure of catalysts and determining how the structure controls their catalytic activities are critical topics in heterogeneous catalysis research. Herein we report that the structure of hydrocalumite-layered double hydroxides (CaAl-LDHs) can be tuned by gradually introducting Ni²⁺. It was revealed that the gradual introduction of Ni²⁺ in hydrocalumite led to a structure-transformation process, which introduced hydrombobomkulite and eventually evolved into takovite. Compared with the case without structure-transformation process, the structure-transformation catalysts showed excellent NH₃ decomposition activity after high-temperature reduction. Moreover, the obtained catalysts showed a relatively high conversion per Ni weight compared with other reported oxide-supported Ni catalysts. This study demonstrates the feasibility of preparing LDHs-based heterogeneous catalysts by modulating the material structure through induced structure-transformation process.     

柱撑型钒基催化剂的制备及其丙烷氧化脱氢催化性能

以人工合成的3种不同层板组成的层状双羟基金属氢氧化物MgAl-CO₃-LDHs、CoAl-CO₃-LDHs和NiCr-CO₃-LDHs为载体，以偏钒酸钠NaVO₃为柱撑剂和钒前体，采用离子交换法制备了钒柱撑的催化剂样品（MgAlVO、CoAlVO和NiCrVO），通过XRD、FTIR、XPS和Raman等手段表征了样品的物相、钒物种的存在形态以及钒的价态，以丙烷氧化脱氢制丙烯为模型反应，表征了所制备的催化剂样品的催化性能，着重探讨了LDHs载体的层板组成以及钒的含量对催化剂样品中的钒氧物种存在形态及其丙烷氧化脱氢催化性能的影响。结果表明：以20%理论含量的钒柱撑MgAl-CO₃-LDHs所制备的催化剂样品20%MgAlVO对丙烷氧化脱氢反应的催化性能较好，当反应温度为560℃时，丙烯收率可以达到11.3%，Raman光谱显示该催化剂样品中的钒以Mg₃V₂O₈和α-Mg₂V₂O₇两种形式共存，且晶格氧O^2-和吸附氧O^-所占的比例较为均衡，有利于获得较好的丙烷氧化脱氢催化性能，而在同样条件下制备的催化剂样品20%CoAlVO和20%NiCrVO中的钒物种只观察到分别以Co₃V₂O₈和Ni₃V₂O₈存在的正钒酸盐，前者对丙烯的收率不到8%，后者甚至完全得不到丙烯。     

两种加料方式下ZnAl-LDHs生长机理研究

含多种金属离子的盐溶液和碱溶液的滴加混合方式会影响反应过程中金属离子的反应活性,进而改变材料的生长过程.分别采用单滴和双滴加料法制备了ZnAl-LDHs.并利用XRD、SEM、FTIR等手段进行表征.在两种加料方式下,研究了加热方式、滴加温度对样品结构、物相、形貌和尺寸的影响.同时探讨了加料方式对ZnAl-LDHs生长的作用机理.研究结果表明:双滴法加料和水浴加热有利于制备单一物相的ZnAl-LDHs片状结构;水热处理易产生ZnO,不利于制备ZnAl-LDHs.     

LDHs对6061铝在不同溶解氧浓度的NaCl溶液中腐蚀行为的影响

通过原位合成法在6061Al合金表面制备了层状双氢氧化物（LDHs）,使用极化曲线（Tafel）和电化学阻抗谱（EIS）研究了在3.5%（质量分数）NaCl溶液中不同溶解氧浓度（1~16 mg/L）下LDHs对6061Al合金腐蚀行为的影响。结果表明,6061Al合金与LDHs/6061Al合金的极化过程均受到溶解氧的扩散控制。随着溶解氧浓度的增加,6061Al合金的腐蚀更加剧烈,其腐蚀电流由1.273 μA增加到了1.743 μA,蚀坑深度由12 μm增加到了19 μm。而LDHs/6061Al合金在各溶解氧浓度下均未观察到蚀坑,这是由于LDHs薄膜阻碍了溶解氧的扩散,其极化过程受到了抑制。此外,随着溶解氧浓度的增加,6061Al合金的阻抗显著增加,这与Al₂O₃的形成有关;而LDHs/6061Al合金的阻抗在不同溶解氧浓度下未发生明显变化,表现出对溶解氧优异的隔绝性能。     

ZnMgAl-CO3-LDHs的沥青阻燃抑烟性能与机理分析

采用层状无卤高效抑烟剂ZnMgAl-CO_3-LDHs制备阻燃沥青,通过热重-差热分析仪、锥形量热仪和X射线光电子能谱仪研究了层状双氢氧化物(LDHs)对沥青阻燃抑烟性能的影响,并分析其阻燃机理.结果表明:掺加质量分数为2%的LDHs可使沥青燃烧的最大热释放速率、平均热释放速率和总烟释放量分别下降24.9%,14.3%和27.0%;LDHs在2%掺量下即有较好的阻燃抑烟效果,而在25%掺量下的阻燃抑烟效果提升有限;LDHs的层状结构可以在沥青燃烧初期降低沥青的失重速率,并提升残渣的完整性、致密性和抗氧化性,但LDHs的热解吸热效应并未在沥青燃烧过程中发挥明显作用.     

Zn/Cr水滑石吸附-可见光催化水中有机污染物

通过共沉淀法合成可循环使用的阴离子粘土材料锌铬水滑石(Zn/Cr LDHs),并借助X射线衍射(XRD),N2吸附-脱附曲线,扫描电子显微镜(SEM)和紫外-可见光漫反射光谱(DRS)等对其进行表征分析。以刚果红为模型污染物,研究了Zn/Cr LDHs去除有机污染物的吸附-可见光光催化活性。通过等温吸附试验,得到Langmuir等温线,其饱和吸附量为426.29 mg/g。Zn/Cr LDHs在氙灯模拟太阳光照射下,每次试验180 min,第5次后脱色率仍高达96.35%,具有良好的可循环使用性。刚果红吸附等温线符合Langmuir模型,吸附过程符合拟二级动力学模型,内扩散为主要控速步骤,吸附过程是自发的放热过程,低温有利于吸附的进行。     

Potential for Layered Double Hydroxides-Based,Innovative Drug Delivery Systems

Layered Double Hydroxides (LDHs)-based drug delivery systems have, for many years, shown great promises for the delivery of chemical therapeutics and bioactive molecules to mammalian cells in vitro and in vivo. This system offers high efficiency and drug loading density, as well as excellent protection of loaded molecules from undesired degradation. Toxicological studies have also found LDHs to be biocompatible compared with other widely used nanoparticles, such as iron oxide, silica, and single-walled carbon nanotubes. A plethora of bio-molecules have been reported to either attach to the surface of or intercalate into LDH materials through co-precipitation or anion-exchange reaction, including amino acid and peptides, ATPs, vitamins, and even polysaccharides. Recently, LDHs have been used for gene delivery of small molecular nucleic acids, such as antisense, oligonucleotides, PCR fragments, siRNA molecules or sheared genomic DNA. These nano-medicines have been applied to target cells or organs in gene therapeutic approaches. This review summarizes current progress of the development of LDHs nanoparticle drug carriers for nucleotides, anti-inflammatory, anti-cancer drugs and recent LDH application in medical research. Ground breaking studies will be highlighted and an outlook of the possible future progress proposed. It is hoped that the layered inorganic material will open up new frontier of research, leading to new nano-drugs in clinical applications.