In-situ Characterisation

Another advantage of XRD is the fact that it can be used in conditions close to those encountered during their use (in situ characterisation). However, if the system is complex, i.e. if there are different extraframework cations or if an adsorbed phase is present, XRD determination is no longer unambiguous [1], Indeed, for X-rays, the intensity diffracted by an element is proportional to its number of electrons which may be the same for two different elements (e.g. Rb+ and Sr23). This is also the reason why the localisation of lighter elements (H, C,. ..) is... 

MBE is a viable epitaxial technique for the growth of nitrides due to its relatively straightforward growth kinetics and excellent controllability aided by in-situ characterisation. The major difference from other growth techniques is its capability for growth at relatively low temperatures, which... 

It is also shown that carbonaceous deposits built upon oxides via spill-over from metal sites is active in ethene hydrogenation in its own right. Thus during catalysis of hydrocarbon reactions some sites (metallic and acidic) are lost or made unavailable while simultaneously others are generated. This complex yet intriguing situation emphasises the need for in-situ characterisation of catalytic surfaces. 

Schlogl R. In situ characterisation of practical heterogeneous catalysis. In Baerns M, editor. Basic principles in applied catalysis. Berlin Springer Verlag 2004. p. 321-60. 

Ravagnan, L. Siviero, F. Lenardi, C. Barborini, E. Milani, P. Casari, C. Li Bassi, A. Bottani, C.E. Cluster beam deposition and in situ characterisation of carbyne-rich films. Phys. Rev. Lett. 2002, 89, 285506-1 to -4. 

Earlier work on the in situ characterisation of rhodium-phosphine/hydrazine complexes was instrumental in the successful outcome of patent litigation between Hovione (Portugal) and Pfizer (USA). Here, we were able to prove conclusively by P, N, and Rh NMR spectroscopies that in the hydrogenation of doxycycline to methacycline, rhodium complexes with N-donor ligands such as 3 and 4 were involved, rather than [RhCl(PPh3)3]." ... 

Sadler, P.J. (1986). Multinuclear NMR Methods for the in situ Characterisation of Chemicai Species. In The Importance of Chemical Speciation in Environmental Processes. In M. Bernhard, F.E. Brinckman and P.J. Sadler (eds). Springer-Verlag, Berlin, Heidelberg, New York. 

Fig. 6.11 Optical appearance and Raman spectra of (a) paracetamol Form III (b) paracetamol Form II, and (c) paracetamol Form I. Reproduced with permission from M. Szelagiewicz etal., In Situ Characterisation of Polymorphic Forms [83] published by Akademiai Kiado Rt. 1999.

Djidja, M-C. Sutton, C.W. Loadman, P.M. Scriven, R Snel, M.R Claude, E. Clench, M.R. Visualisation and in situ characterisation of proteins in adenocarcinoma tissue sections by direct MALDl-mass spectrometry imaging. Proc. 56th ASMS Conference on Mass Spectrometry and Allied Topics, Denver, CO, June 1-5, 2008, WP 169. 

Price SWT, Speed JD, Kannan P, Russell AE (2011) Exploring the first steps in core-shell electrocatalyst preparation in situ characterisation of the underpotential deposition of Cu on supported Au nanoparticles. J Am Chem Soc 133 19448-19458... 

Golay, S., R. Doepper, and A. Renken, In-situ characterisation of the surface intermediates for the ethanol dehydration reaction over yalumina under dynamic conditions. Appl. Catalysis A General, 1998.172 97-106. 

In order attain measurable SHG signals, pulsed femtosecond lasers with large intensities are usually employed (Yan et al. 1998 Schneider et al. 2007). It was possible to show that the SHG scales with surface potential and the independently measured zeta-potentials can be reproduced by adopting appropriate models for the electric double layer (Yan et al. 1998). More generally, SHG is directly related to the surface excess of adsorbate as shown for malachite green on polystyrene (Eckenrode et al. 2005). This technique offers the opportunily for online and in situ characterisation of colloidal suspensions with particle sizes considerably larger than 5 nm (Schneider and Peukert 2007 Schiirer and Peukeit 2010). 

Safi M, Chazalviel J-N, Cherkaoui M, Belai di A, Gorochov O (2002) Etching of n-type silicon in (HF + oxidant) solutions in situ characterisation of surface chemistry. Electrochim Acta... 

Introduction and overview The solid oxide fuel cell Ex-situ characterisation studies In-situ characterisation studies Conclusion and outlook References... 

D.S. Hussey and D.L. Jacobson, Neutron radiography for high resolution studies in low temperature fuel cells , in Polymer electrolyte membrane and direct methanol fuel cell technology. Volume 2 In situ characterisation techniquesfor low temperature fuel cells. Ch. 7. (2012) WoodheadPubhshing, Oxford. 

Self-supporting pressed discs of the pure oxide powders are prepared for in situ characterisation studies by transmission/absorption IR spectroscopy. These samples are put onto the IR beam, in an appropriate cell allowing heating, cooling, and gas/vapour manipulation. Activation is mostly performed by outgassing at relatively high temperatures. In the case of diffuse reflectance infrared Fourier transform (DRIFT) experiments the pure catalyst powder is deposited on the sample holder, with smooth pressure, and activation is mostly performed by an inert, dry gas flow. 

Grob et al. [172] have reported the analysis of polyols in a pilot plant operation using a fibre optic transmission probe. Free epoxide (unreacted) and hydroxyl number were monitored to enable cost and safety control during full-scale production. The feasibility of NIR-ATR spectroscopy for the in situ characterisation of epoxy/amine cure reactions has been demonstrated [173]. 

In recent years, techniques for direct analysis of the non-polymer components have developed apace and it has become increasingly important for scientists, engineers and technicians to have a basic grounding in these methods. This treatise is concerned with the in situ characterisation of additives embedded in a broad variety of polymeric matrices and evaluates critically the extensive problem-solving experience and state-of-the-art in the polymer industry. Despite well-deserved attention and considerable efforts direct polymer/additive analysis (without separation) has not yet turned into a great many general and routinely workable concepts. Nevertheless, the future foresees a greater share for in-polymer analysis. 

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