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Heterogeneous catalyst

Quan Lu, Yanjuan Zhang, Huayu Hu, Wen Wang, Zuqiang Huang, Dong Chen, Mei Yang, Jing Liang
To rapidly obtain a stable Fe₃O₄@cellulose heterogeneous Fenton catalyst, a novel in situ chemical co-precipitation method was developed. Compared with mechanical activation (MA)-pretreated cellulose (MAC), MA + FeCl₃ (MAFC)-pretreated cellulose (MAFCC) was more easily dissolved and uniformly distributed in NaOH/urea solvent. MAFCC and MAC solutions were used as precipitators to prepare Fe₃O₄@MAFCC and Fe₃O₄@MAC nanocomposites, respectively. MAFCC showed stronger interaction and more uniform combination with Fe₃O₄ nanoparticles than MAC, implying that MAFC pretreatment enhanced the accessibility, reactivity, and dissolving capacity of cellulose thus, provided reactive sites for the in situ growth of Fe₃O₄ nanoparticles on the regenerated cellulose...
February 16, 2019: Nanomaterials
Maximilian Franz Hertrich, Florian Korbinian Scharnagl, Anahit Pews-Davtyan, Carsten Kreyenschulte, Henrik Lund, Stephan Bartling, Ralf Jackstell, Matthias Beller
Hydroformylation of olefins has been studied in the presence of specific heterogeneous cobalt nanoparticles. The catalytic materials were prepared by pyrolysis of preformed cobalt complexes deposited onto different inorganic supports. AAS-measurements indicate a correlation of catalyst activity and cobalt leaching as well as a strong influence of the heterogeneous support on the productivity. These novel, low-cost, easy to handle catalysts can substitute more toxic, unstable and volatile cobalt carbonyl complexes for hydroformylations on lab-scale...
February 19, 2019: Chemistry: a European Journal
Manickam Selvaraj, Mohammed A Assiri
The major product, 2,3,5-trimethyl-1,4-benzophenone (TMB[double bond, length as m-dash]O), was synthesised by an eco-friendly liquid-phase oxidation of 2,3,6-trimethylphenol (TMP-OH) over Cu(ii)-containing propylsalicylaldimine (CSA) functionalized mesoporous solid catalysts, namely, CSASBA-15(0.2), CSASBA-15(0.1) and CSAMCM-41(0.2), synthesized using various amounts of copper in a simple post-grafting method using different mesoporous silica materials, e.g., thick-silica walled SBA-15 and thin-silica walled MCM-41...
February 19, 2019: Dalton Transactions: An International Journal of Inorganic Chemistry
Jakub Trawiński, Robert Skibiński
In this study TiO2 -mediated photocatalytic degradation of the persistent drug clozapine under the simulated solar radiation was studied for the first time. The experiments were conducted both in the ultrapure and river water, which enabled the assessment of the organic matrix impact. The direct and indirect photolysis experiments were conducted for a comparison. Influence of the catalyst loading on the efficiency of the process was also assessed, and the highest catalyst loading (300 mg L-1 ) was found to be the most effective...
February 10, 2019: Science of the Total Environment
Pramod V Chavan, Uday V Desai, Prakash P Wadgaonkar, Savita R Tapase, Kisan M Kodam, Amit Choudhari, Dhiman Sarkar
A series of spirochromenocarbazole tethered 1,2,3-triazoles were synthesized via click chemistry based one-pot, five component reaction between N-propargyl isatins, malononitrile, 4-hydroxycarbazole, aralkyl halides and sodium azide using cellulose supported CuI nanoparticles (Cell-CuI NPs) as the heterogeneous catalyst. Antiproliferative activity of all the synthesized compounds was investigated against panel of cancer cell lines such as MCF-7, MDA-MB-231, HeLa, PANC-1, A-549, and THP-1. Many of the synthesized compounds exhibited good anti-proliferative activity against breast (MCF-7 and MDA-MB-231) and cervical (HeLa) cancer cells with IC50 values less than 10 μM...
February 8, 2019: Bioorganic Chemistry
Xiaoming Zhang, Yiting Hou, Rammile Ettelaie, Ruqun Guan, Ming Zhang, Yabin Zhang, Hengquan Yang
We describe a novel method to prepare a liquid-solid hybrid catalyst via interfacial growth of a porous silica crust around Pickering emulsion droplets, which allowed us to overcome the current limitations of both homogeneous and heterogeneous catalysts. The inner micron-scaled liquid (for example, ionic liquids) pool of the resultant catalyst can host free homogeneous molecular catalysts or enzymes to create a true homogeneous catalysis environment. The porous silica crust of the hybrid catalyst has excellent stability, which makes it amenable to packing directly in fixed-bed reactors for continuous flow catalysis...
February 18, 2019: Journal of the American Chemical Society
Vijay Gupta, Sanjay K Mandal
Using achiral components, a V-shaped dicarboxylic acid (H2 L) and a conformationally flexible bidentate linker (bpp), a thermally stable chiral metal organic framework {[Cd(bpp)(L)(H2 O)]·DMF} n (1), where H2 L = 4,4'-(dimethylsilanediyl)bis-benzoic acid, bpp = 1,3-bis(4-pyridyl)propane and DMF = N,N-dimethylformamide, has been solvothermally synthesized and crystallographically characterized. It consists of 1D helical chains linked at the cadmium centers resulting in an overall 2D framework. Its microporous nature was confirmed by gas-sorption measurements...
February 18, 2019: Inorganic Chemistry
Ali Reza Sardarian, Milad Kazemnejadi, Mohsen Esmaeilpour
New Fe3O4@SiO2 core-shell superparamagnetic nanoparticles functionalized by a bis-salophen Schiff base Pd complex were synthesized and employed as an efficient magnetic nanocatalyst in the Heck and Sonogashira cross coupling reactions. The synthesized nanostructures were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), dynamic light scattering (DLS), energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), elemental analysis (CHN), cyclic voltammetry (CV), Brunauer-Emmett-Teller analysis (BET), and UV-vis spectroscopy...
February 18, 2019: Dalton Transactions: An International Journal of Inorganic Chemistry
Gong-Jun Chen, Wen-Ling Xin, Jing-Si Wang, Jun-Yan Cheng, Yu-Bin Dong
Herein, a new Ag nanoparticle (Ag NP) loaded organic molecular cage is reported. The obtained Ag@1 can act as a highly efficient heterogeneous catalyst for the selective reduction of nitroarenes to azo compounds under visible-light irradiation.
February 18, 2019: Chemical Communications: Chem Comm
Xiaoxiong Cai, Qionghao Xu, Gaomei Tu, Yanghe Fu, Fumin Zhang, Weidong Zhu
The synthesis of heterogeneous cooperative catalysts in which two or more catalytically active components are spatially separated within a single material has generated considerable research efforts. The multiple functionalities of catalysts can significantly improve the efficiency of existing organic chemical transformations. Herein, we introduce ruthenium (Ru) nanoparticles (NPs) on the surfaces of a metal-organic framework pre-encapsulated with polyoxometalate silicotungstic acid (SiW) UiO-66 (University of Oslo [UiO]) and prepared a 2...
2019: Frontiers in Chemistry
Hongliang Li, Menglin Wang, Laihao Luo, Jie Zeng
Single-atom catalysts provide an ideal platform to bridge the gap between homogenous and heterogeneous catalysts. Here, the recent progress in this field is reported from the perspectives of static regulation and dynamic evolution. The syntheses and characterizations of single-atom catalysts are briefly discussed as a prerequisite for catalytic investigation. From the perspective of static regulation, the metal-support interaction is illustrated in how the supports alter the electronic properties of single atoms and how the single atoms activate the inert atoms in supports...
February 6, 2019: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
Jiafei Lyu, Xuan Zhang, Ken-Ichi Otake, Xingjie Wang, Peng Li, Zhanyong Li, Zhijie Chen, Yuanyuan Zhang, Megan C Wasson, Ying Yang, Peng Bai, Xianghai Guo, Timur Islamoglu, Omar K Farha
Tetratopic organic linkers have been extensively used in Zr-based metal-organic frameworks (MOFs) where diverse topologies have been observed. Achieving meticulous control over the topologies to tune the pore sizes and shapes of the resulting materials, however, remains a great challenge. Herein, by introducing substituents to the backbone of tetratopic linkers to affect the linker conformation, phase-pure Zr-MOFs with different topologies and porosity were successfully obtained under the same synthetic conditions...
January 28, 2019: Chemical Science
Lucila I Doumic, Micaela Génova, Gregor Žerjav, Albin Pintar, Miryan C Cassanello, Hernán E Romeo, María A Ayude
A novel hierarchically structured composite aimed as a stable catalyst for the heterogeneous Fenton-type (HFT) oxidation process was developed by using a cost-effective and versatile technique. Prussian Blue nanoparticles (PBNP) were dispersed onto aligned macroporous TiO2 (rutile) monoliths prepared via directional freezing of aqueous dispersions of TiO2 nanoparticles. The catalytic performance was evaluated in the HFT oxidation of an azo dye frequently used as a model contaminant, Orange G (OG). Experiments were carried out in a liquid batch-recycle reactor, in which the liquid flow rate was set to ensure negligible external mass transfer resistance...
February 13, 2019: Journal of Environmental Management
Qiang Fu, Claudia Draxl
Single-atom catalysts (SACs) combine the best of two worlds by bridging heterogeneous and homogeneous catalysis. The superior catalytic properties of SACs, however, can hardly be exploited without a suitable substrate. Here, we explore the possibility of using hybrid organic-inorganic perovskites as supporting materials for single transition-metal atoms. By means of first-principles calculations, we predict that single Pt atoms can be incorporated into methylammonium lead iodide surfaces by replacing the methylammonium groups at the outermost layer...
February 1, 2019: Physical Review Letters
Ying Liu, Deli Wu, Hongping He
Catalytic ozonation has been widely used for refractory dye wastewater treatment due to highly reactive HO·. In this study, a kind of low-cost and environmental-friendly modified ceramsite sphere derived from pyrite cinder, silty clay and kaolin was prepared as ozonation catalyst. The degradation performances of cation red x-GRL were performed under a continuous mode. Being close to the practical treatment, continuous-flow ozonation study is vital for applying heterogeneous catalytic ozonation in wastewater treatment at a large industrial scale...
December 2018: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Senkuttuvan Rajendiran, Vinothkumar Ganesan, Sungho Yoon
The synthesis of a unique heterogeneous catalyst that combines the functionality of a homogeneous catalyst and the advantages of a heterogeneous catalytic process is a continuing goal in various industrially applicable reactions. Here, we report heterogenization of homogeneous catalyst for lactone production from epoxide carbonylation through a facile polymerization using Friedel-Crafts reaction. A correlation between reactivity and degree of heterogeneity has been deduced by synthesizing different sized polymeric catalysts...
February 15, 2019: Inorganic Chemistry
Kristian E Dalle, Julien Warnan, Jane J Leung, Bertrand Reuillard, Isabell S Karmel, Erwin Reisner
The synthesis of renewable fuels from abundant water or the greenhouse gas CO2 is a major step toward creating sustainable and scalable energy storage technologies. In the last few decades, much attention has focused on the development of nonprecious metal-based catalysts and, in more recent years, their integration in solid-state support materials and devices that operate in water. This review surveys the literature on 3d metal-based molecular catalysts and focuses on their immobilization on heterogeneous solid-state supports for electro-, photo-, and photoelectrocatalytic synthesis of fuels in aqueous media...
February 15, 2019: Chemical Reviews
Sara G S Santos, Larissa O Paulista, Tânia F C V Silva, Madalena M Dias, José Carlos B Lopes, Rui A R Boaventura, Vítor J P Vilar
This work focuses on the intensification of BrO3 - (200 μg L-1 ) reduction by TiO2 -assisted heterogeneous photocatalysis, using the NETmix mili-photoreactor illuminated by UVA light-emitting diodes (UVA-LEDs). The mili-photoreactor was assembled in two configurations: i) catalyst deposition on the channels and chambers of a back stainless steel slab (SSS) and ii) catalyst deposition on the front borosilicate glass slab (BGS), allowing the study of front-side (FSI) and back-side (BSI) illumination mechanisms, respectively...
February 5, 2019: Science of the Total Environment
Xin Li, Jiaguo Yu, Mietek Jaroniec, Xiaobo Chen
Photoreduction of CO2 into sustainable and green solar fuels is generally believed to be an appealing solution to simultaneously overcome both environmental problems and energy crisis. The low selectivity of challenging multi-electron CO2 photoreduction reactions makes it one of the holy grails in heterogeneous photocatalysis. This Review highlights the important roles of cocatalysts in selective photocatalytic CO2 reduction into solar fuels using semiconductor catalysts. A special emphasis in this review is placed on the key role, design considerations and modification strategies of cocatalysts for CO2 photoreduction...
February 14, 2019: Chemical Reviews
Xiao Liu, Jiaqiang Yang, Gurong Shen, Meiqing Shen, Yunkun Zhao, Kyeongjae Cho, Bin Shan, Rong Chen
The interfacial structure of metal-oxide composite catalysts plays a vital role in heterogeneous catalysis, which is crucial to the adsorption and activation of reactants. Herein, the interfacial effects of bare and Fe/Co/Ni doped SmMn2O5 mullite oxide supported Pt clusters on CO oxidation have been investigated by first-principles based microkinetics analysis. A robust formation of Pt/Mn2 trimer structures is demonstrated at the bifunctional interfaces irrespective of the Ptn cluster's size, which can provide spatially separated sites for CO adsorption and O2 dissociation...
February 14, 2019: Nanoscale
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