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layered double hydroxide

Zhisheng Gao, Keiko Sasaki, Xinhong Qiu
The structural memory effect of layered double hydroxides (LDHs) is one of the important reasons for their extensive use in environmental remediation. In this study, humic acid (HA) was extracted from black soil and sediments and characterized to determine their structures. The regeneration mechanisms of calcinated LDHs (CLDHs) including different divalent metals (Mg-CLDH and Zn-CLDH) in deionized water and different HA solutions were carefully elucidated, and the reasons for the behavior differences in the two materials were explained...
April 23, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Lei Cao, Jintang Guo, Jianhua Tian, Yang Xu, Miaomiao Hu, Chun Guo, Meiyu Wang, Jinjie Fan
Synthetic polymer fluid loss additive (FLA), an important type of admixture, was broadly applied in modern well cementation. However, the filter loss volume and fluidity of cement pastes containing polymer-FLA would deteriorate remarkably when sea water was used in mixing slurries instead of fresh water. In this study, a novel sustained-release-type fluid loss additive(S-FLA) was synthesized by means of anion-exchange intercalation reaction between an anionic type-copolymer and a calcium/aluminum type-Layered Double Hydroxide (Ca/Al-LDH)...
April 4, 2018: Journal of Colloid and Interface Science
Michael Ertl, Corina Andronescu, Jonathon Moir, Mirijam Zobel, Friedrich E Wagner, Stefan Barwe, Geoffrey Ozin, Wolfgang Schuhmann, Josef Breu
Mössbauerite is investigated for the first time as an "iron only" mineral for the electrocatalytic oxygen evolution reaction in alkaline media. The synthesis proceeds via intermediate mixed-valence green rust that is rapidly oxidized in situ while conserving the layered double hydroxide structure. The material catalyzes the oxygen evolution reaction on a glassy carbon electrode with a current density of 10 mA cm-2 at 1.63 V versus the reversible hydrogen electrode. Stability measurements as well as post-electrolysis characterization are presented...
April 20, 2018: Chemistry: a European Journal
Fang-Shuai Zhang, Jia-Wei Wang, Jun Luo, Rui-Rui Liu, Zhi-Ming Zhang, Chun-Ting He, Tong-Bu Lu
The development of highly efficient, low-cost and stable electrocatalysts for overall water splitting is highly desirable for the storage of intermittent solar energy and wind energy sources. Herein, we show for the first time that nickel can be extracted from NiFe-layered double hydroxide (NiFe-LDH) to generate an Ni2 P@FePO x heterostructure. The Ni2 P@FePO x heterostructure was converted to an Ni2 P@NiFe hydroxide heterostructure (P-NiFe) during water splitting, which displays high electrocatalytic performance for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1...
February 7, 2018: Chemical Science
Yangziwan Weng, Shanyue Guan, Heng Lu, Xiangmin Meng, Abdessamad Y Kaassis, Xiaoxue Ren, Xiaozhong Qu, Chenghua Sun, Zheng Xie, Shuyun Zhou
It is a great challenge to develop multifunctional nanocarriers for cancer diagnosis and therapy. Herein, versatile CDs/ICG-uLDHs nanovehicles for triple-modal fluorescence/photoacoustic/two-photon bioimaging and effective photothermal therapy were prepared via a facile self-assembly of red emission carbon dots (CDs), indocyanine green (ICG) with the ultrathin layered double hydroxides (uLDHs). Due to the J-aggregates of ICG constructed in the self-assembly process, CDs/ICG-uLDHs was able to stabilize the photothermal agent ICG and enhanced its photothermal efficiency...
July 1, 2018: Talanta
Yuxiang Qin, Liping Wang, Xiaofei Wang
Layered double hydroxides (LDHs) are recently revealed to be promising in gas sensor application due to compositional flexibility and unique 2D-interlayer channel for gas diffusion and adsorption. This work demonstrates a kind of highly porous hierarchical LDHs containing Mg2+ and Al3+ (MgAl-LDHs) for ethanol-sensing at room temperature. The MgAl-LDHs with unique flower-like hierarchical structure and mesoporous interlayer were synthesized hydrothermally using sodium dodecyl sulfate (SDS) as soft template as well as intercalating agent...
April 18, 2018: Nanotechnology
Martina Salzano de Luna, Giovanna Giuliana Buonocore, Chiara Giuliani, Elena Messina, Gabriella Di Carlo, Marino Lavorgna, Luigi Ambrosio, Gabriel M Ingo
The photodegradation kinetics of 2-mercaptobenzothiazole (MBT), a corrosion inhibitor for copper-based alloys, is studied for the first time in high amorphous polyvinyl alcohol coatings subjected to either UV irradiation or indoor light exposure. The photodegradation process proceeds rapidly, thus compromising the anticorrosion ability of the coating. We prove that the encapsulation of MBT into layered double hydroxide (LDH) nanocarriers slows down its decomposition kinetics by a factor 3. Besides preserving the corrosion inhibitor, such a strategy allows a controlled release of MBT triggered by corrosion-related stimuli, e...
April 17, 2018: Angewandte Chemie
Bryan M Hunter, Jay R Winkler, Harry B Gray
Efficient catalysis of the oxygen-evolution half-reaction (OER) is a pivotal requirement for the development of practical solar-driven water splitting devices. Heterogeneous OER electrocatalysts containing first-row transition metal oxides and hydroxides have attracted considerable recent interest, owing in part to the high abundance and low cost of starting materials. Among the best performing OER electrocatalysts are mixed Fe/Ni layered double hydroxides (LDH). A review of the available experimental data leads to the conclusion that iron is the active site for [NiFe]-LDH-catalyzed alkaline water oxidation...
April 14, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Xiufei Zhao, Chenggang Niu, Lei Zhang, Hai Guo, Xiaoju Wen, Chao Liang, Guangming Zeng
In this study, Co-Mn layered double hydroxide (Co-Mn LDH) was synthesized, characterized, and tested as heterogeneous catalyst to activate peroxymonosulfate (PMS) for degradation of organic dyes. The results of characterization showed that Co-Mn LDH had high purity, uniform morphology and large specific surface area (49.9379 m2 /g). The degradation experiments demonstrated that five different dyes with the concentration of 50 mg/L could be decomposed completely within 240 s using only 0.025 g/L of Co-Mn LDH and 0...
April 6, 2018: Chemosphere
Hyo-Jin Ahn, Anandarup Goswami, Francesca Riboni, Stepan Kment, Alberto Naldoni, Shiva Mohajernia, Radek Zboril, Patrik Schmuki
Over the past years, α-Fe2O3 (hematite) has re-emerged as a promising photoanode material in photoelectrochemical (PEC) water splitting. In spite of considerable success in obtaining relatively high solar conversion efficiency, the main drawbacks hindering practical application at hematite are related to an intrinsically hampered charge transport and a sluggish kinetics of the oxygen evolution reaction on the photoelectrode surface. In the present work, we report a strategy how to synergistically address both these critical limitations...
April 12, 2018: ChemSusChem
Pengzhan Sun, Renzhi Ma, Takayoshi Sasaki
Ion conducting membranes/electrolytes have been employed extensively in some important industrial and biological systems, especially in fuel cells, water electrolyzers, gas separation, sensors and biological selective ion transport, acting as one of the core components and sometimes directly determining the device performance. However, the traditional polymeric proton exchange membranes (PEMs)/anion exchange membranes (AEMs) suffer from highly toxic preparation procedures, poor thermal and chemical stabilities, and unsatisfactory ion conductivities...
January 7, 2018: Chemical Science
Mir Tamzid Rahman, Tomohito Kameda, Shogo Kumagai, Toshiaki Yoshioka
Nitrate-intercalated MgAl layered double hydroxide (LDH) was successfully delaminated in water by a facile and effective method upon reflux at 120 °C for 24 h followed by sonication at 40 °C for 5 h. This process is environmentally friendly since water is the only solvent used. The delaminated nanosheets were characterized by microscopic, spectroscopic, and particle size analyses. The delamination process successfully produced octahedron-shaped single-layer nanosheets 50-150 nm in size. X-ray photoelectron spectroscopy (XPS) data confirmed that the surface elements and their chemical status are consistent with the basic layer of MgAl LDH...
March 28, 2018: Chemosphere
Liang Xu, Zhe Wang, Xu Chen, Zongkai Qu, Feng Li, Wensheng Yang
The development of non-precious metal electrocatalysts for renewable energy conversion and storage is compelling but greatly challenging due to low activity of the existing catalysts. Herein, the ultrathin NiAl-layered double hydroxide nanosheets (NiAl-LDH-NSs) are prepared by simple liquid-exfoliation of bulk NiAl-LDHs and first used as ethanol electrooxidation catalysts. The ultrathin two-dimensional (2D) structure ensures that the LDH nanosheets expose a greater number of active sites. More importantly, much Ni(III) active species (NiOOH) in the ultrathin nanosheets are formed by the exfoliation process, which play an authentic catalytic role in the ethanol oxidation reaction (EOR)...
January 10, 2018: Electrochimica Acta
Jing Wang, Qingfeng Yang, Liang Zhang, Manshun Liu, Na Hu, Wentao Zhang, Wenxin Zhu, Rong Wang, Yourui Suo, Jianlong Wang
In order to develop an accurate and precise determination method based on solid phase extraction of Pb(II) in food and water samples, a hybrid monolithic column based on layered double hydroxides (LDHs) nanosheets-alginate hydrogel has been synthesized. Combining the advantages of porous 3D framework of hydrogel with selective adsorption of LDHs toward Pb(II), the hydrogel-based hybrid monolithic column shows enhanced enrichment selectivity and efficiency for target ions. Effects of hydrogel composition, pH, concentration and type of eluent, sample volume, and interfering ions on the recoveries of the analytes were also investigated...
August 15, 2018: Food Chemistry
Yanyan Yang, Xiao Du, Xiaowei An, Shengqi Ding, Feifan Liu, Zhonglin Zhang, Xuli Ma, Xiaogang Hao, Guoqing Guan, Hui Zhang
In this study, CoNi-layered double hydroxide (CoNi-LDH) nanosheets coated conducting polypyrrole (PPy) nanowire was controllably fabricated on Pt plate or carbon cloth by using unipolar pulse electrodeposition (UPED) method and served as a novel electrochemically switched ion exchange (ESIX) hybrid film with proton-ligand effect for the removal of perchlorate anions (ClO4 - ). It is expected that the space among CoNi-LDH nanosheets of the shell could act as the reservoir for the anions while the PPy core serve as the potential-induced element for proton-ligand...
March 29, 2018: Journal of Colloid and Interface Science
Yanyong Wang, Man Qiao, Yafei Li, Shuangyin Wang
Intrinsically inferior electrocatalytic activity of NiFe layered double hydroxides (LDHs) nanosheets is considered as a limiting factor to inhibit the electrocatalytic properties for oxygen evolution reaction (OER). Proper defect engineering to tune the surface electronic configuration of electrocatalysts may significantly improve the intrinsic activity. In this work, the selective formation of cation vacancies in NiFe LDHs nanosheets is successfully realized. The as-synthesized NiFe LDHs-VFe and NiFe LDHs-VNi electrocatalysts show excellent activity for OER, mainly attributed to the introduction of rich iron or nickel vacancies in NiFe LDHs nanosheets, which efficiently tune the surface electronic structure increasing the adsorbing capacity of OER intermediates...
April 3, 2018: Small
Cecilia Vasti, Laura V Bonnet, Mauricio R Galiano, Ricardo Rojas, Carla E Giacomelli
Considering that the use of nanoparticles (NPs) as carriers of therapeutic or theranostic agents has increased in the last years, it is mandatory to understand the interaction between NPs and living systems. In contact with biological fluids, the NPs (synthetic identity) are covered with biomolecules that form a protein corona, which defines the biological identity. It is well known that the protein corona formation is mediated by non-specific physical interactions, but protein-protein interactions (PPI), involving specific recognition sites of the polypeptides, are also involved...
March 26, 2018: Colloids and Surfaces. B, Biointerfaces
Fumihiko Ogata, Noriaki Nagai, Yukine Kariya, Eri Nagahashi, Yuhei Kobayashi, Takehiro Nakamura, Naohito Kawasaki
In this study, we prepared Fe-Mg-type hydrotalcites (Fe-HT3.0 and Fe-HT5.0) with different molar ratios and evaluated their adsorption capability for nitrite and nitrate ions from aqueous solution. Fe-HT is a typical hydrotalcite-like layered double hydroxide. Adsorption isotherms, as well as the effects of contact time and pH were investigated, and it was found that Fe-HT can adsorb larger amounts of nitrite and nitrate ions than Al-HT (normal-type hydrotalcite). Adsorption isotherm data were fitted to both Freundlich (correlation coefficient: 0...
2018: Chemical & Pharmaceutical Bulletin
Maryam Shamsayei, Yadollah Yamini, Hamid Asiabi, Meysam Safari
The authors describe a 3-component nanoparticle system composed of a silica-coated magnetite (Fe3 O4 ) core and a layered double (Cu-Cr) hydroxide nanoplatelet shell. The sorbent has a high anion exchange capacity for extraction anionic species. A simple online system, referred to as "on-line packed magnetic-in-tube solid phase microextraction" was designed. The nanoparticles were placed in a stainless steel cartridge via dry packing. The cartridge was then applied to the preconcentration acidic drugs including naproxen and indomethacin from urine and plasma...
February 22, 2018: Mikrochimica Acta
Wenxian Gou, Matthew G Siebecker, Zimeng Wang, Wei Li
Trace metals (e.g. Ni, Zn) leached from industrial and agricultural processes are often simultaneously present in contaminated soils and sediments. Their mobility, bioavailability, and ecotoxicity are affected by sorption and cosorption at mineral/solution interfaces. Cosorption of trace metals has been investigated at the macroscopic level, but there is not a clear understanding of the molecular-scale cosorption processes due to lack of spectroscopic information. In this study, Ni and Zn cosorption to aluminum oxides (γ-Al2 O3 ) in binary-sorbate systems were compared to their sorption in single-sorbate systems as a function of pH using both macroscopic batch experiments and synchrotron-based X-ray absorption fine structure spectroscopy...
March 27, 2018: Geochemical Transactions
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