Archive for the ‘Inorganic’ Category

Coordinating nature and photochemistry to create hydrogen

When we look to our future energy resources, the need to realise new means of renewable energy is immediately obvious. Much research is being carried out around the world into the development of systems that can generate energy – from H2 to biofuels to solar fuels – all of which place great importance on high efficiency and sustainability.

Looking at the world around us for inspiration, the obvious candidate is the photosynthetic process, where visible light is employed to convert CO2 and H2O into chemical energy. This process involves the transport of electrons through a complex series of intricately aligned porphyrin-related and protein biomolecules. We can explore the development of a system that mimics the behaviour of natural systems, with respect to the relay of electrons along a series of molecules, or, alternatively, we can take the components in these systems and exploit their properties in combination with other electronically-active but non-natural molecules.

Upon photoexcitation of [Ru(bpy)3]2+, electron transfer through a ferredoxin scaffold to a cobaloxime catalyst facilitates the production of hydrogen.It is the latter approach which Lisa Utschig and her team from Argonne National Laboratory, near Chicago in the US, employed to generate a molecular system capable of photocatalysing the production of hydrogen. In their biohybrid system, the photosensitiser ruthenium(II) tris(bipyridine), ferredoxin (a water-soluble electron transfer protein), and cobaloxime (a cobalt(II)-based catalyst), were combined to generate a miniature reaction center that mimics those which occur in biological systems. However, the Utschig group’s system has a smaller molecular weight, which allows for characterisation of the electronic processes that occur in the system.

Lisa and her colleagues found that the presence of ferredoxin in the catalytic system acted as a scaffold to stabilise the charge-separated state necessary for electron transfer and the desired production of H2. They also observed that the catalytic behaviour of the Ru(II)–Co(II) pair was only possible in the presence of ferredoxin, which acted to extend the lifetime of the otherwise transient Co(I), allowing the desired reaction to occur.

In order to fully understand and enhance the properties of the molecular systems developed to fulfil the increasing need for energy alternatives, we need to be able to probe the structure and processes that occur in the molecule; the use of smaller analogs to those that exist in nature offers a means by which to achieve this goal. The photoactivated catalyst discussed in this work is an important step forward in the development of an optimized system for use in solar fuel production.

Read this hot ChemComm article in full:
Aqueous light driven hydrogen production by a Ru–ferredoxin–Co biohybrid
S. R. Soltau, J. Niklas, P. D. Dahlberg, O. G. Poluektov, D. M. Tiede, K. L. Lulfort and L. M. Utschig
Chem. Commun., 2015, 51, 10628–10631
DOI: 10.1039/C5CC03006D

Biography

Anthea Blackburn is a guest web writer for Chemical Science. She hails originally from New Zealand, and is a recent graduate student of Northwestern University in the US, where she studied under the tutelage of Prof. Fraser Stoddart (a Scot. There, she exploited supramolecular chemistry to develop multidimensional systems and study the emergent properties that arise in these superstructures. When time and money allow, she is ambitiously attempting to visit all 50 US states.

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Rotaxane Pulley – To Me, To You

Mechanically interlocked molecules have received ever increasing focus over the last number of years due to their potential to mimic the function of macroscopic devices in the molecular world.

Examples include molecular elevators and molecular muscles and with this Communication Zheng Meng and Chuan-Feng Chen of the CAS Key Laboratory of Molecular Recognition and Function at the Chinese Academy of Sciences in Beijing have added pulley-like shuttling motion to the toolkit.

Molecular pulley system powered by acid and base

Molecular pulley system powered by acid and base

Using their previously reported* triptycene-derived crown ether host and combining it with a linear guest with three dibenzylammonium and three N-methyltriazolium sites, they have made a molecular pulley system that mimics the plain rotary motion and linear translocation of full sized pulleys. The movement is powered by acid or base leading to one end of the cable-like guest moving towards the host while the other moves away (picture).

The researchers have not only added to the toolbox of molecular motion components but also provided new insights towards further developing molecular machines.

If you want to make your own molecular pulley read the article today! 

To read the details, check out the ChemComm article in full – it’s free to access until 10th May:
A molecular pulley based on a triply interlocked [2]rotaxane
Zheng Meng and Chuan-Feng Chen
Chem. Commun., 2015, 51, Advance Article
DOI: 10.1039/C5CC01301A


*(a) C. F. Chen, Chem. Commun., 2011, 47, 1674–1688 RSC; (b) Y. Han, Z. Meng, Y. X. Ma and C. F. Chen, Acc. Chem. Res., 2014, 47, 2026–2040

**Access is free through a registered RSC account – click here to register

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A collection of papers in memory of Professor Robert Williams

Professor Robert Williams, Oxford, inorganic, Biological ChemistryProfessor Robert (Bob) Williams died this March at the age of 89. He was a true pioneer in the field of bio-inorganic chemistry – especially concerning the role of calcium as a biological messenger – and contributed substantially to our understanding of the evolution of life. Professor Williams was often considered as one of the first people to start thinking about metallomics as a field, and will be greatly missed amongst his peers.

In memory of Professor Williams’ huge contribution to the field, we have collated a number of his publications across Metallomics, Dalton Transactions and ChemComm below. We hope you enjoy revisiting some of his exceptional work.

Copper proteomes, phylogenetics and evolution, L. Decaria, I. Bertini, R.J.P. Williams, Metallomics, 2011, 56–60

Zinc proteomes, phylogenetics and evolution, L. Decaria, I. Bertini, R.J.P. Williams, Metallomics, 2010, 706–709

A chemical systems approach to evolution, R.J.P. Williams, Dalton Transactions, 2007, 991–1001

Metallo-enzyme catalysis, R.J.P. Williams, Chemical Communications, 2003, 1109–1113

The chemical elements of life, R.J.P. Williams, Journal of the Chemical Society, Dalton Transactions, 1991, 539–546

Temperature study of the solution conformations of aqueous lanthanide(III) complexes containing monodentate ligands, A.L. Du Preez, S. Naidoo, R.J.P. Williams, Journal of the Chemical Society, Dalton Transactions, 1988, 2315–2321

A proton NMR study of some CoII complexes containing the N-hexadecyl-iminodiacetate ligand, C.J. Rix, R.J.P. Williams, Journal of the Chemical Society, Chemical Communications, 1986, 203–205

Solution conformation of aqueous lanthanide(III)-antipyrine complexes, A.L. Du Preez, R.J.P. Williams, Journal of the Chemical Society, Dalton Transactions, 1986, 1425–1429

Precipitation within unilamellar vesicles. Part 1. Studies of silver(I) oxide formation, S. Mann, R.J.P. Williams, Journal of the Chemical Society, Dalton Transactions, 1983, 311–316

Precipitation within unilamellar vesicles. Part 2. Membrane control of ion transport, S. Mann, M.J. Kime, R.G. Ratcliffe, R.J.P. Williams, Journal of the Chemical Society, Dalton Transactions, 1983, 771–774

The characterisation of the nature of silica in biological systems, S. Mann, C.C. Perry, R.J.P. Williams, C.A. Fyfe, G.C. Gobbi, G.J. Kennedy, Journal of the Chemical Society, Chemical Communications, 1983, 168–170

New organo-metallic reagents for electron microscopy, S. Mann, R.J.P. Williams, P.R. Sethuraman, M.T. Pope, Journal of the Chemical Society, Chemical Communications, 1981, 1083–1084

Solid state phosphorus NMR spectroscopy of minerals and soils, R.J.P. Williams, R.G.F. Giles, A.M. Posner, Journal of the Chemical Society, Chemical Communications, 1981, 1051–1052

Electron relaxation rates of lanthanide aquo-cations, B.M. Alsaadi, F.J.C. Rossotti, R.J.P. Williams, Journal of the Chemical Society, Dalton Transactions, 1980, 2147–2150

Hydration of complexone complexes of lanthanide cations, B.M. Alsaadi, F.J.C. Rossotti, R.J.P. Williams, Journal of the Chemical Society, Dalton Transactions, 1980, 2151–2154

Preparation of Ag2O crystallites within phospholipid vesicles and their use in nucleation studies, J.L. Hutchison, S. Mann, A.J. Skarnulis, R.J.P. Williams, Journal of the Chemical Society, Chemical Communications, 1980, 634–635

Studies of lanthanide (III) dipicolinate complexes in aqueous solution. Part 2. Hydration, B.M. Alsaadi, F.J.C. Rossotti, R.J.P. Williams, Journal of the Chemical Society, Dalton Transactions, 1980, 813–816

Studies of lanthanide(III) pyridine-2,6-dicarboxylate complexes in aqueous solution. Part 1. Structures and 1H nuclear magnetic resonance spectra, B.M. Alsaadi, F.J.C. Rossotti, R.J.P. Williams, Journal of the Chemical Society, Dalton Transactions, 1980, 597–602

Location of biological compartments by high resolution NMR spectroscopy and electron microscopy using magnetite-containing vesicles, S. Mann, A.J. Skarnulis, R.J.P. Williams, Journal of the Chemical Society, Chemical Communications, 1979, 1067–1068

Mapping organic molecules in biological space by high resolution NMR spectroscopy and electron microscopy, A.J. Skarnulis, P.J. Strong, R.J.P. Williams, Journal of the Chemical Society, Chemical Communications, 1978, 1030–1032

An investigation of some potential uses of the gadolinium(III) ion as a structural probe, E.C.N.F. Geraldes, R.J.P. Williams, Journal of the Chemical Society, Dalton Transactions, 1977, 1721–1726

Structure of lanthanide(III) mono- and bis-dipicolinates in solution, B.M. Alsaadi, F.J.C. Rossotti, R.J.P. Williams, Journal of the Chemical Society, Chemical Communications, 1977, 527–529

Assignment of the NMR spectrum of iron(III) protoporphyrin IX dicyanide using paramagnetic shift and broadening probes, J.G. Brassington, R.J.P. Williams, P.E. Wright, Journal of the Chemical Society, Chemical Communications, 1975, 338–340

Conformational studies of peroxidase-substrate complexes. Structure of the indolepropionic acid-horseradish peroxidase complex, P.S. Burns, R.J.P. Williams, P.E. Wright, Journal of the Chemical Society, Chemical Communications, 1975, 795–796

The temperature dependence of some physical properties of cobinamides and cobalamins, S.A. Cockle, O.D. Hensens, H.A.O. Hill, R.J.P. Williams, Journal of the Chemical Society, Dalton Transactions, 1975, 2633–2634

Conformational studies of lanthanide complexes with carboxylate ligands, B.A. Levine, J.M. Thornton, R.J.P. Williams, Journal of the Chemical Society, Chemical Communications, 1974, 669–670

Ethylenediaminetetra-acetato-lanthanate(III), -praesodimate(III), -europate(III), and -gadolinate(III) complexes as nuclear magnetic resonance probes of the molecular conformations of adenosine 5′- monophosphate and cytidine 5′-monophosphate in solution, C.M. Dobson, R.J.P. Williams, A.V. Xavier, Journal of the Chemical Society, Dalton Transactions, 1974, 1762–1764

Intramolecular nuclear Overhauser effects in proton magnetic resonance spectra of proteins, I.D. Campbell, C.M. Dobson, R.J.P. Williams, Journal of the Chemical Society, Chemical Communications, 1974, 888–889

Lanthanoid(III) cations as nuclear magnetic resonance conformational probes: Studies on cytidine 5′-monophosphate at pH 2, C.D. Barry, C.M. Dobson, R.J.P. Williams, A.V. Xavier, Journal of the Chemical Society, Dalton Transactions, 1974, 1765-1769

Nuclear magnetic resonance spectra of dimeric cupric compounds, W. Byers, R.J.P. Williams, Journal of the Chemical Society, Dalton Transactions, 1973, 555–560

Separation of contact and pseudo-contact contributions to shifts induced by lanthanide(III) ions in nuclear magnetic resonance spectra, C.M. Dobson, R.J.P. Williams, A.V. Xavier, Journal of the Chemical Society, Dalton Transactions, 1973, 2662–2664

The effect of 1,3,5-trinitrobenzene on 1H nuclear magnetic resonance and electron paramagnetic resonance spectra of some cobalt(II) porphyrins, H.A.O. Hill, P.J. Sadler, R.J.P. Williams, Journal of the Chemical Society, Dalton Transactions, 1973, 1663–1667

Origin of lanthanide nuclear magnetic resonance shifts and their uses, B. Bleaney, C.M. Dobson, B.A. Levine, R.B. Martin, R.J.P. Williams, A.V. Xavier, Journal of the Chemical Society, Chemical Communications, 1972, 791b–793

The chemistry of vitamin B12. Part XVI. Binding of thiols to the cobalt(II) corrins, S. Cockle, H.A.O. Hill, S. Ridsdale, R.J.P. Williams, Journal of the Chemical Society, Dalton Transactions, 1972, 297–302

A method of assigning 13C nuclear magnetic resonance spectra using europium(III) ion-induced pseudocontact shifts and C-H heteronuclear spin decoupling techniques, B. Birdsall, J. Feeney, J.A. Glasel, R.J.P. Williams, A.V. Xavier, Journal of the Chemical Society D: Chemical Communications, 1971, 1473–1474

Methylation by methyl vitamin B12, G. Agnes, S. Bendle, H.A.O. Hill, F.R. Williams, R.J.P. Williams, Journal of the Chemical Society D: Chemical Communications, 1971, 850–851

Kinetics of substitution of co-ordinated carbanions in cobalt(III) corrinoids, H.A.O. Hill, J.M. Pratt, S. Ridsdale, F.R. Williams, R.J.P. Williams, Journal of the Chemical Society D: Chemical Communications, 1970, 341

Thallium(I) as a potassium probe in biological systems, J.P. Manners, K.G. Morallee, R.J.P. Williams, Journal of the Chemical Society D: Chemical Communications, 1970, 965–966

The lanthanide cations as nuclear magnetic resonance probes of biological systems, K.G. Morallee, E. Nieboer, F.J.C. Rossotti, R.J.P. Williams, A.V. Xavier, R.A. Dwek, Journal of the Chemical Society D: Chemical Communications, 1970, 1132–1133

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Bubble power: Driving self-propelled machines with acetylene bubbles

Self-propelled micro/nanomachines were once the thing of science-fiction, but as so often is the case, fiction has become reality in recent years. Such devices could in the future find uses in environmental remediation and biomedical applications. Researchers around the world have been making progress on designing these machines, and it is a novel fuel-free autonomous self-propelled motor which is the focus of this Chemical Communication by Martin Pumera and team from the School of Physical and Mathematical Sciences at Nanyang Technological University.

Rather than focus on oxygen bubble propulsion, which often requires the use of high levels of toxic hydrogen peroxide, they have developed an acetylene bubble based motor. To achieve this they utilised the reaction of water and calcium carbide, which produces acetylene and calcium hydroxide. This approach makes use of the water that will be found in the most common application environments, but does not require reactive metals such as magnesium and aluminium. The work expands the scope of bubble-propulsion beyond hydrogen and oxygen and gives designers of micro/nanomachines greater power unit choices in their designs.

Acetylene bubble powered motor in water.

The most important part of the research reported in this Communication is the optimisation of an encapsulation layer around the calcium carbide to control the reaction. However, to find out what this layer is made of and how to prepare it you will have to read the article today.

To read the details, check out the Chem Comm article in full:

Acetylene bubble-powered autonomous capsules: towards in situ fuel
James Guo Sheng Moo, Hong Wang and Martin Pumera
Chem. Commun., 2014, 50, Advance Article
DOI: 10.1039/C4CC07218A
   

    

    

    

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Just Mix – Zeolitic Imidazolate Framework Synthesis

Zeolitic-imidazolate frameworks (ZIFs) are a sub-class of metal-organic frameworks (MOFs) with a wide range of potential uses including: CO2 capture, storage, catalysis, sensing and biomedicine. Unfortunately their synthesis often requires additives or reaction activation, and if they can be made without these it often requires long reaction times or results in low yields, neither of which is ideal for a substance with such wide potential uses.

To overcome this bottleneck in ZIF synthesis, Roland Fischer and his team from the Inorganic Chemistry department in Ruhr Universitat Bochum in Germany have developed a rapid room temperature synthesis approach. I am a great believer in developing approaches that can be carried out at room temperature and pressure and this is one such elegant solution. The authors produce nanocrystals of ZIFs in a very narrow size distribution by careful selection of the precursors and the solvents they are dissolved in. The solutions are then mixed and stirred to create the ZIF crystals; it really is that elegant.

ZIF crystals showing very narrow size distribution

The authors then used these crystals to fabricate thin films on quartz crystal microbalances and used this device to detect volatile organic solvents. This demonstration leads the way into exploring other uses of these ZIFs – after all, they can now be easily made. But to find out which solvent and precursors you need to use, you’ll have to read the paper today!

To read the details, check out the ChemComm article in full:
Rapid room temperature synthesis of zeolitic-imidazolate framework (ZIF) nanocrystals
Min Tu, Christian Wiktor, Christoph Rosler and Roland Fischer
Chem. Commun., 2014, 50, 13258-13260
DOI: 10.1039/C4CC06491G  

    

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ChemComm Emerging Investigator Lectureship: Louise Berben

Professor Louise A. Berben (University of California Davis, USA) was one of the recipients of the 2013 ChemComm Emerging Investigator Lectureships.

ChemComm Lectureship

ChemComm Lectureship recipient Louise Berben with Deputy Editor Jane Hordern

Louise has just completed her lectureship tour which took her to Imperial College London and the University of Bristol in the UK; she concluded her tour by giving a plenary lecture at Challenges in Inorganic and Materials Chemistry (ISACS13), in Dublin, Ireland. Congratulations Louise!

Our annual lectureship recognises an emerging scientist in the early stages of their independent academic career.

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Metal-organic frameworks (MOFs): ChemComm web-themed issue

We would like to celebrate with our authors and the community our web themed collection entitled “Metal-organic frameworks” recently published in ChemComm.

The issue was Guest Edited by Neil Champness (University of Nottingham, UK), Christian Serre (University of Versailles, France) and Seth Cohen (University of California, San Diego, USA), and contains an impressive collection of articles, including:

Feature Articles:

MOFs for CO2 capture and separation from flue gas mixtures: the effect of multifunctional sites on their adsorption capacity and selectivity
Zhijuan Zhang, Yonggang Zhao, Qihan Gong, Zhong Li and Jing Li
Chem. Commun., 2013, 49, 653-661, DOI: 10.1039/C2CC35561B

Commercial metal–organic frameworks as heterogeneous catalysts
Amarajothi Dhakshinamoorthy, Mercedes Alvaro and Hermenegildo Garcia
Chem. Commun., 2012, 48, 11275-11288, DOI: 10.1039/C2CC34329K

Communications:

Understanding excess uptake maxima for hydrogen adsorption isotherms in frameworks with rht topology
David Fairen-Jimenez, Yamil J. Colón, Omar K. Farha, Youn-Sang Bae, Joseph T. Hupp and Randall Q. Snurr
Chem. Commun., 2012, 48, 10496-10498, DOI: 10.1039/C2CC35711A

Targeted functionalisation of a hierarchically-structured porous coordination polymer crystal enhances its entire function
Kenji Hirai, Shuhei Furukawa, Mio Kondo, Mikhail Meilikhov, Yoko Sakata, Osami Sakata and Susumu Kitagawa
Chem. Commun., 2012, 48, 6472-6474, DOI: 10.1039/C2CC31421E

Take a look at the excellent work published in this themed collection: http://rsc.li/cc-mofs

We encourage you to share the link to this collection with your colleagues.

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The chemists’ enzyme

The title of this post was taken from the website of Barry Trost, one of the world’s leading scientists and author of an astonishing 924 papers. Describing his work, he states:

One major activity in designing new reactions and reagents involves the development of “chemists’ enzymes” – non-peptidic transition metal based catalysts that can perform chemo-, regio-, diastereo-, and especially enantioselective reactions.

Chemists have, for a long time, sought to reproduce the incredible feats of nature. Natural biology has evolved over many years to achieve the efficiency and reactivity that most lab-based chemists could only dream of. Nature achieves this by employing incredibly sophisticated enzymes which are, sadly, almost impossible to replicate by a synthetic chemist due to their complexity. An alternative idea is to use these enzymes as inspiration for new catalysts and try to focus on the general reasons why they work rather than trying to create direct copies.

Supramolecular catalysts for decarboxylative hydroformylation and aldehyde reduction.

Dr Bernhard Breit, Lisa Diab and Urs Gellrich at Albert-Ludwigs-Univertat in Germany have shown in a HOT ChemComm article that a highly selective catalyst can be created when combining a metal catalyst with a directing ligand to control the reaction. In this Communication, they report excellent results using  rhodium, the classic metal of choice for hydroformylation, and a functional group for recognition of the substrate. The net effect of these features combined is that the substrate is held in a specific way at the catalytic site. As a result, the reaction which follows can only occur in a specific way. This is similar to how enzymes control the chirality.

The concept behind this catalyst is one which could be applied to a great number of different reactions – no doubt we can look forward to reading about these in the near future.

Read this HOT ChemComm article today!

Tandem decarboxylative hydroformylation–hydrogenation reaction of α,β-unsaturated carboxylic acids toward aliphatic alcohols under mild conditions employing a supramolecular catalyst system
Lisa Diab, Urs Gellrich and Bernhard Breit
Chem. Commun., 2013, Advance Article
DOI: 10.1039/C3CC45547E, Communication

Ruaraidh McIntosh is a guest web-writer for ChemComm.  His research interests include supramolecular chemistry and catalysis.  When not working as a Research Fellow at Heriot-Watt University, Ruaraidh can usually be found in the kitchen where he has found a secondary application for his redoubtable skills in burning and profanity.

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Mind the gap – Enhancing intercalation of luminescent aggregates

Particular molecules, which are not luminescent in solution, can luminesce intensely upon molecular aggregation; this is known as aggregation-induced emission (AIE). AIE luminogens are used widely as efficient electroluminescent materials, sensitive chemosensors, and as bioprobes. The main cause of the AIE effect is the restriction of intramolecular rotation. Therefore it can be promoted by introducing the molecules into inorganic materials with a rigid skeleton such as α-zirconium phosphate layers.

Jihong Yu and colleagues from Jilin University in China have published a method describing the intercalation of a quaternary tetraphenylethene (TPEN) cation, an AIE chromophore, into α-zirconium phosphate. At first glance, this does not seem to be too difficult a task– after all, the TPEN has two permanent positive charges on either end suitable to interact with the negatively charged phosphate layers. But, in this case, size does matter. The chromophore is almost three times larger than the distance between phosphate layers, more than a tight fit!

Stretching the layers of α-zirconium phosphate by preintercalation of butylamine before introduction of the chromophore

To overcome this problem, Yu and colleagues carried out a preintercalation step with butylamine before performing a cation exchange step to place the TPEN chromophore within the phosphate layers. Ultimately, they stretched the layer before putting the final molecule inside, just like you would stretch a pair of shoes in an effort to make them fit before placing your sensitive feet inside.

The intercalated product was found to be highly emissive in the blue region of the electromagnetic spectrum and was readily internalized by cells. The system also showed good biocompatibility, suggesting that it would make an excellent base for fluorescent labels in future biomedical imaging applications.

To read the details, check out the HOT Chem Comm article in full:

AIE cation functionalized layered zirconium phosphate nanoplatelets: ion-exchange intercalation and cell imaging

Dongdong Li, Chuanlong Miao, Xiaodan Wang, Xianghui Yu, Jihong Yu and Ruren Xu
Chem. Commun., 2013, 49, Accepted Manuscript
DOI: 10.1039/C3CC45041D

Iain Larmour is a guest web writer for ChemComm.  He has researched a wide variety of topics during his years in the lab including nanostructured surfaces for water repellency and developing nanoparticle systems for bioanalysis by surface enhanced optical spectroscopies.  He currently works in science management with a focus on responses to climate change.  In his spare time he enjoys reading, photography and art.

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A cloak of many carbons

Catalysts can be exceedingly useful in the real world, from treating our car’s exhaust fumes to creating fertilisers.  There are many ways to make catalysts and even multiple ways to make the same catalyst.  The path that you choose to a catalyst can have a significant impact on the quality of the end product.

Eloy del Rio and team from the Structure and Chemistry of Nanomaterials group at the University of Cadiz in Spain have investigated ceria-based oxide-supported gold catalysts for carbon monoxide oxidation.  The routine for depositing the metal phase onto the oxide support and the subsequent catalyst activation step can ultimately affect the activity of the catalyst.  Catalysts prepared by deposition-precipitation with urea followed by activation under oxidising conditions result in significantly more activity than those prepared under reducing conditions.

Variation in catalyst activity under oxidising and reducing activation protocols.

This had previously been observed by others, but the reason for the difference was never discussed.  The authors set out to find out why the activity differed.  They used a suite of nano-analytical and nano-structural techniques to probe the catalysts, finding that the catalyst prepared under reducing conditions had a coat of amorphous carbon which severely hampered the catalyst activity.  This could be removed by a re-oxidation treatment that burnt away the carbon layer and produced an active catalyst similar to the one produced under oxidising conditions.

The precipitating agent used in the synthesis can also influence the resulting activities of catalysts prepared via the deposition-precipitation method.  No difference between oxidising and reducing activations is observed when sodium carbonate is used in place of urea.

To read the details, check out the ChemComm article in full:

Dramatic effect of redox pre-treatments on the CO oxidation activity of Au/Ce0.50Tb0.12Zr0.38O2-x catalysts prepared by deposition-precipitation with urea: a nano-analytical and nano-structural study
E. del Rio, M. López-Haro, J.M. Cies, J.J. Delgado, J.J. Calvino, S. Trasobares, G. Blanco, M.A. Cauqui and S. Bernal
Chem. Commun., 2013, 49, Accepted Manuscript
DOI: 10.1039/C3CC42051e

Iain Larmour is a guest web writer for ChemComm.  He has researched a wide variety of topics during his years in the lab including nanostructured surfaces for water repellency and developing nanoparticle systems for bioanalysis by surface enhanced optical spectroscopies.  He currently works in science management with a focus on responses to climate change.  In his spare time he enjoys reading, photography and art.

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