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Laboratoire de Réactivité de Surface
UMR 7197 UPMC-CNRS

Sarah Petit

Domaine d’expertise

Sciences des Matériaux

Catalyse

Physique et Chimie des Matériaux

 

→ Sujet de la thèse 

Influence de la conduction ionique sur le contrôle de la réactivité des hydroxyapatites

 

→ Financement 

Dim OxyMORE

Coordonnées

Courriel(s) : sarah.petit@upmc.fr

Fonction et rattachement

Doctorant / CNRS

Carrière

Au LRS depuis le 15 octobre 2014

Publications

Incorporation of vanadium into the framework of hydroxyapatites: importance of the vanadium content and pH conditions during the precipitation step

By: Petit, Sarah; Gode, Thrimurthulu; Thomas, Cyril; Dzwigaj, Stanislaw; Millot, Yannick; Brouri, Dalil; Krafft, Jean-Marc; Rousse, Gwenaelle; Laberty-Robert, Christel; Costentin, Guylene

Physical Chemistry Chemical Physics - Volume19 - Issue14 - Pages 9630-9640

 

Even though vanadium-​modified hydroxyapatite (V-​HAp) samples are promising systems for oxidative dehydrogenation of propane, the incorporation of vanadium into the hydroxyapatite framework was reported to be limited and to lead to over-​stoichiometric compds.  Here, the synthesis of a Ca10(PO4)​6-​x(VO4)​x(OH)​2 stoichiometric solid soln. using a co-​pptn. method is monitored in the whole compn. range (0 ≤ x ≤ 6) by controlling the pH of the pptn. medium, with continuous (the first series of samples) or periodic (the second series of samples) addn. of NH4OH during the pptn. step or during the maturation step, resp.  The changes in pH conditions result in materials of a substantial difference in terms of the final compn.  From x-​ray diffraction patterns and Rietveld refinements, a solid soln. V-​HAp phase was exclusively obtained for the first series of samples for x varying from 0 to 6.  This also occurred in the second series of samples but only for x lower than 4.  For 4 ≤ x ≤ 5.22, the materials were composed of a mixt. of V-​HAp and Ca2V2O7, whereas for a x value of 6 only Ca2V2O7 was formed.  The predominance of polymeric V species in soln. at a high vanadium concn. deduced from the diagram of speciation of vanadium accounts for the preferential formation of Ca2V2O7 under these particular conditions.  However, provided that a higher pH value was maintained, isolated VO3(OH)​2-​ species are predominant, which accounts for the incorporation of isolated vanadates into the hydroxyapatite framework and for the well-​controlled stoichiometry with Ca​/(P + V) ratios close to 1.67.  Such a good accommodation of vanadium in the hydroxyapatite framework is illustrated by the characterization of the local surrounding of phosphorus and vanadium species using 31P and 51V NMR, Raman and UV-​vis spectroscopies.

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IMPC

Fête de la Sciences

13/09/17

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