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Nano Catalyst

Xiaohui Xu, Li Sun, Bo Bai, Honglun Wang, Yourui Suo
With the abundant use of pesticides in agriculture and grassland farming, water contamination unavoidably occurs due to the leaching of pesticide residues into environment. Now, most of the research on degradation of nitroaromatic pesticides residues has focused on nano catalysis-based method, however, effective post-reaction separation and recycling of the tiny nanocatalysts is also a significant technological challenge to be addressed. Herein, we report a simple and versatile strategy for the construction of efficient and recyclable catalysts of polydopamine (PDA)@Ag/polystyrene (PS) films for degradation of pesticides based on multi-purpose PDA microspheres inspired by mussel adhesion...
February 8, 2019: Science of the Total Environment
Liao Xu, Yang Gu, Yaoyi Li, Huaizhi Liu, Yangyang Shang, Yinyan Zhu, Bo Zhou, Lihua Zhu, Xiaoqing Jiang
HYPOTHESIS: Recently, molybdenum disulfide (MoS2 ) as a new type of catalyst, has been used for hydrogen evolution. In order to overcome the shortcomings of MoS2 , such as poor conductivity and lack of catalytic activity sites, various materials were added to prepare composites, such as graphene with good conductivity. EXPERIMENTS: In this work, we combined MoS2 with graphene through a very simple liquid-phase salt-assisted co-exfoliation method. The obtained MoS2 /graphene nano-composites have been further applied to electrocatalyst of hydrogen evolution reaction...
February 7, 2019: Journal of Colloid and Interface Science
Zhimao Wu, Gang Yang, Erzhen Mu, Qiuchen Wang, Sebastiaan A Meijer, Zhiyu Hu
Combustion is a chemical reaction that emits heat and light. Nanofire is a kind of flameless combustion that occurs on the micro-nano scale. Pt/Al2 O3 film with a thickness of 20 nm can be prepared as a catalyst by micro-nano processing. When the methanol-air mixture gas passes through the surface of the catalyst, a chemical reaction begins and a significant temperature rise occurs in the catalyst region. Compared to macroscopic combustion, Nanofire has many special properties, such as large temperature gradients, uniform temperature distribution, and fast temperature response...
February 15, 2019: Nano Convergence
Sudhakar Ranganathan, Sivakumar Thiripuranthagan
Nanosized ZSM-5/AlKIT-6 composite catalyst which comprises of both mesoporous large pore 3D KIT-6 and coke resistant microporous ZSM-5 was synthesized using simple in-situ overgrowth method. AlKIT-6 were coated over nano ZSM-5 with different coating ratios (5%, 10% and 15%) and utilized for biofuel production from non-edible Jatropha curcas oil using catalytic cracking technology. The morphology, porosity, acidity and Si/Al ratio of the synthesized catalysts were characterized using analytical techniques like SEM, TEM, XRD, BET, FTIR, ICP-AES and TPD...
July 1, 2019: Journal of Nanoscience and Nanotechnology
Nagaraju Pasupulety, Hafedh Driss, Mohammed Raoof A Rafiqui, Abdulrahim A Al-Zahrani, Muhammad A Daous, Arshid M Ali, Sharif F Zaman, Lachezar A Petrov
Silver catalysts supported on ceria-zirconia (CZ) mechanically mixed oxide were synthesized by wet impregnation and chelating methods. Nominal loadings of 5 wt.% of Ag was deposited on the CZ support. These catalysts were tested for the CO₂ hydrogenation reaction to methanol with feed gas composition of CO₂-H₂ = 3:1 at 250 °C, 20 bar total pressure and GHSV of 1800 h-1 . The calcined and reduced catalysts were characterized using XRD, BET, TPR, SEM-EDS, XPS and FTIR-DRIFTs techniques. Finely deposited silver crystallites sized in the range of 20-50 nm were observed through SEM and HR-TEM analysis...
June 1, 2019: Journal of Nanoscience and Nanotechnology
Yong Sun, Zhipeng Lin, Shao Hong Peng, Valérie Sage, Zhi Sun
In this paper, we aim to focus on the utilization of carbon dioxide (CO₂) as a feedstock for synthetic applications in chemical and fuel industries, through catalytic carboxylation and reduction reactions. Thermal catalytic conversion as well as non-thermal plasma assisted and photocatalytic conversion CO₂ into fuels such as methane, methanol, and long-chain hydrocarbons using different catalyst especially nano catalyst are also thoroughly compared and reviewed in this paper. Among currently available technical routes, the thermal catalytic conversion of CO₂ via the Fischer-Tropsch (FT) synthesis using nanoscale catalyst offers the most feasible, practical and mature alternative for industrial-scale applications on the short term basis, converting gigantic quantity of CO₂ captured from power plants into hydrocarbons...
June 1, 2019: Journal of Nanoscience and Nanotechnology
Nimrod Harpak, Guy Davidi, Dan Schneier, Svetlana Menkin, Edna Mados, Diana Golodnitsky, E Peled, Fernando Patolsky
Here, we report on the large scale one-step preparation, characterization and application of three-dimensional sponge-like silicon alloy composite anodes, based on the catalyst-free growth of porous silicon nano-networks directly onto highly conductive and flexible open-structure stainless steel current collectors. By the use of a key hydrofluoric acid-based chemical pre-treatment process, the originally non-catalytic stainless steel matrix becomes nano-porous and highly self-catalytic, thus greatly promoting the formation of a silicon sponge-like network at unexpectedly low growth temperatures, 380-460oC...
February 11, 2019: Nano Letters
Manyi Gao, Yongsheng Yu, Weiwei Yang, Ji Li, Shichong Xu, Ming Feng, Haibo Li
The development of a robust and low-cost non-noble metal catalyst for photocatalytic H2 evolution is of great importance for practical applications. In this study, monodisperse Ni nanoparticles of controlled sizes were prepared by a facile method and anchored on graphitic carbon nitride (g-C3N4) nanosheets via a self-assembly route. The noble-metal-free Ni/g-C3N4 composite catalysts exhibit excellent photocatalytic activities for the hydrolytic dehydrogenation of ammonia borane (AB) under visible light. An optimum AB hydrolysis rate was obtained when the size of the Ni NPs was 3...
February 11, 2019: Nanoscale
Yang Wang, Yinlong Zhu, Sepideh Afshar, Meng Wai Woo, Jing Tang, Timothy Williams, Biao Kong, Dongyuan Zhao, Huanting Wang, Cordelia Selomulya
CoS2-MoS2 nanoflakes decorated MoO2 (CoMoOS) hybrid submicro-wires with rich active interfaces were synthesized via the sulfuration of CoMoO4. They showed excellent activity while synergistically catalyzing the hydrogen evolultion reaction (HER) in basic media by promoting both the water dissociation and hydrogen absorption steps. Thus, the CoMoOS catalysts only needed 123 mV to achieve 10 mA cm-2 with a small Tafel slope in alkaline solutions, and required 1.68 V to obtain the same current density when assembled into an alkaline electrolyser...
February 11, 2019: Nanoscale
Ting Ting Zhao, Zhong Wei Jiang, Shu Jun Zhen, Cheng Zhi Huang, Yuan Fang Li
A bimetallic organic gel was prepared by mixing the bridging ligand 2,4,6-tri(4-carboxyphenyl)-1,3,5-triazine with Cu(II) and Co(II) ions at room temperature. The resulting metal-organic gel (MOG) shows enhanced peroxidase-like activity, most likely due to the synergetic redox cycling between Co(III)/Co(II) and Cu(II)/Cu(I) pairs. These accelerate interfacial electron transfer and generation of hydroxy radicals. The MOG can catalyze the reaction of H2 O2 with terephthalic acid (TPA), producing a blue fluorescence product with the maximum excitation/emission at 315/446 nm...
February 9, 2019: Mikrochimica Acta
Luning Chen, Xibo Zhang, Jinhong Zhou, Zhaoxiong Xie, Qin Kuang, Lansun Zheng
Tandem catalysis (i.e., a process in which a desirable product is synthesized by a one-step process consisting of sequential reactions) has attracted intensive attention owing to its sustainable green and atom-economical characteristics. In this process, the utilization of a high-efficiency multifunctional catalyst is key. However, different functional sites integrated within the catalyst are required to be rationally designed and precisely engineered to guarantee the synergy between the catalytic reactions...
February 5, 2019: Nanoscale
Hongming He, Qian-Qian Zhu, Chuanqi Zhang, Ying Yan, Jing Yuan, Jing Chen, Cheng-Peng Li, Miao Du
It is a great challenge to rationally integrate multiple reactive sites into a composite material with confined nano-space, which can be applied as a nanoreactor to facilitate targeting catalytic reaction. In this work, an ionic metalloporphyrin has been in situ encapsulated into ZIF-8 for the solvent-free synthesis of cyclic carbonates from CO2 and epoxides without any co-catalyst under 1 atm CO2.
February 4, 2019: Chemistry, An Asian Journal
Dongsheng Lu, Junhao Li, Chaohui Lin, Jinyun Liao, Yufa Feng, Zitian Ding, Zhiwei Li, Quanbing Liu, Hao Li
Yolk-shell structured micro/nano-sized materials have broad and important applications in different areas due to their unique spatial configurations. In this study, yolk-shell structured Co3 O4 @Co3 O4 is prepared using a simple and scalable hydrothermal reaction, followed by a calcination process. Then, Cox Cu1- x Co2 O4 @Coy Cu1- y Co2 O4 microspheres are synthesized via adsorption and calcination processes using the as-prepared Co3 O4 @Co3 O4 as the precursor. A possible formation mechanism of the yolk-shell structures is proposed based on the characterization results, which is different from those of yolk-shell structures in previous study...
February 4, 2019: Small
A Ramesh, P Tamizhdurai, S Gopinath, K Sureshkumar, E Murugan, K Shanthi
Magnetically recoverable Au nanoparticles immobilized/stabilized on core-shell nanocomposites are synthesized by the combination of suspension polymerization as well as surface initiator atom transfer radical polymerization (SI-ATRP) methods. The magnetic core-shell supported Au nanocatalysts are namely Fe3 O4 -PAC-AuNPs, Fe3 O4 -PVBC-g-PAC-AuNPs, Fe3 O4 -HEA-AuNPs, and Fe3 O4 -PVBC-g-HEA-AuNPs. Among all the catalysts, Fe3 O4 -PVBC-g-PAC-Au NPs exhibited an excellent activity in the reduction of Rhodamine B with an apparent rate constant of 10...
January 2019: Heliyon
Caiqin Wang, Ke Zhang, Hui Xu, Yukou Du, M Cynthia Goh
Renewable alcohol oxidation is of vital significance for clean energy conversion and storage. Here, we fabricated a three-dimensional (3D) nanonet-like hybrid catalyst combining Au nanoparticles and poly(3,4-ethylenedioxythiophene) (PEDOT) together, in which PEDOT nanonets act as the framework of the 3D catalyst and the support for the dispersion of Au nanoparticles. The catalyst was designated as Au-PEDOT. By using conductive carbon cloth (CC) as electrode substrates, the as-fabricated Au-PEDOT/CC electrodes were applied to evaluate the electrocatalytic activity towards ethanol and 2-propanol in the alkaline media, respectively...
January 16, 2019: Journal of Colloid and Interface Science
Robinson Dinamarca, Rodrigo Espinoza-González, Cristian H Campos, Gina Pecchi
The type of metal oxide affects the activity and selectivity of Fe₂O₃⁻SiO₂⁻MeO₂⁻Pt (Me = Ti, Sn, Ce) catalysts on the hydrogenation of cinnamaldehyde. The double shell structure design is thought to protect the magnetic Fe₂O₃ cores, and also act as a platform for depositing a second shell of TiO₂, SnO₂ or CeO₂ metal oxide. To obtain a homogeneous metallic dispersion, the incorporation of 5 wt % of Pt was carried out over Fe₂O₃⁻SiO₂⁻MeO₂ (Me = Ti, Sn, Ce) structures modified with (3-aminopropyl)triethoxysilane by successive impregnation-reduction cycles...
January 29, 2019: Materials
Yahya Absalan, Mikhael A Ryabov, Olga V Kovalchukova
In this study, synthesis of bimetallic (Co, Mn, and Ni) complexes of salicylic acid (L1 ) and 1,2 dihydroxybenzene (L2 ) based on titanium(IV) were investigated, then the samples were decomposed by thermal method to obtain Mx Tiy Oz nanoparticles (M = Ni, Co, and Mn). The samples in complexes mode were analyzed by UV-Vis (200-800 nm), FT-IR (4000-400 Cm-1 ), CHN analysis and the structure of the bimetallic compounds also were investigated by the Quantum-chemical modelling. In addition, the samples in nanoparticles mode were studied by thermal analysis (to obtain DTA curves), XRD, FESEM image and EDX analyzing...
April 2019: Materials Science & Engineering. C, Materials for Biological Applications
Hojat Veisi, Sirous Razeghi, Pourya Mohammadi, Saba Hemmati
Surface modification of Fe3 O4 nanoparticle with thiol groups was used for the immobilization of silver nano-particles to produce Fe3 O4 /SiO2 -Pr-S-Ag NPs. The prepared catalyst was characterized by Inductively coupled plasma (ICP), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectrum (EDS), vibrating sample magnetometer (VSM) and Fourier transform infrared (FTIR) analysis. In this fabrication, thio-groups played an important role as a capping and stabilizing agent for Ag nanoparticles...
April 2019: Materials Science & Engineering. C, Materials for Biological Applications
Wolfgang Junge
Cyanobacteria and plants carry out oxygenic photosynthesis. They use water to generate the atmospheric oxygen we breathe and carbon dioxide to produce the biomass serving as food, feed, fibre and fuel. This paper scans the emergence of structural and mechanistic understanding of oxygen evolution over the past 50 years. It reviews speculative concepts and the stepped insight provided by novel experimental and theoretical techniques. Driven by sunlight photosystem II oxidizes the catalyst of water oxidation, a hetero-metallic Mn4CaO5(H2O)4 cluster...
January 2019: Quarterly Reviews of Biophysics
Lijun Zheng, Shizheng Zheng, Hongrui Wei, Lingling Du, Zhengyou Zhu, Jian Chen, Dachi Yang
Efficient, stable electrode catalysts and advanced hydrogen sensing materials are the core of the hydrogen production and hydrogen detection for guaranteeing the safe issues. Although a universal material to achieve the above missions is highly desirable, it remains challenging. Here, we report palladium/bismuth/copper hierarchical nano-architectures (Pd/Bi/Cu HNAs) for advanced dual-applications towards hydrogen evolution reaction (HER) and hydrogen detection, via first electrodeposition of cylindrical nanowires and subsequently wet-chemical etching art...
January 22, 2019: ACS Applied Materials & Interfaces
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