تفاصيل الوثيقة

نوع الوثيقة : مقال في مجلة دورية 
عنوان الوثيقة :
Activation and local structural stability during the thermal decomposition of Mg/Al-hydrotalcite by total neutron scattering
Activation and local structural stability during the thermal decomposition of Mg/Al-hydrotalcite by total neutron scattering
 
الموضوع : كيمياء 
لغة الوثيقة : الانجليزية 
المستخلص : The activation of synthetic hydrotalcite, the carbonated layered double hydroxide (LDH) with ratio Mg 2+/Al 3+ = 3 and structural formula [Mg 6Al 2(OH) 16] 2+· CO 3 2-n(H 2O), has been investigated using neutron and X-ray diffraction. In situ neutron diffraction was used to follow the structural phase transformations during the thermal decomposition (calcination) of hydrotalcite under vacuum in the temperature range 298-723 K, and during which the residual gas evolved by the sample was analysed by mass spectrometry. Detailed structural information of the LDH and mixed metal oxides (MMOs) was extracted from both the Bragg peaks and the total scattering. These two analysis techniques provide complementary insight into the relevant transition mechanisms, since Bragg diffraction originates from long-range periodicities within the samples while total scattering reveals the subtleties of the local atomic environment. This latter information is particularly important for our understanding of catalytic activity since it elucidates the local metal coordination. We find that, during the calcination process, the local environment around the metal centres is robust, as the various stages during the phase transition have identical local structures. The implications of these new results for the nature of the MMOs is discussed in relation to the well-studied, reverse, rehydration reaction, and the high propensity of trivalent Al ions to migrate to tetrahedrally-coordinated lattice sites. 
ردمد : 0959-9428 
اسم الدورية : Journal of Materials Chemistry 
المجلد : 21 
العدد : 39 
سنة النشر : 1432 هـ
2011 م 
نوع المقالة : مقالة علمية 
تاريخ الاضافة على الموقع : Saturday, April 14, 2012 

الباحثون

اسم الباحث (عربي)اسم الباحث (انجليزي)نوع الباحثالمرتبة العلميةالبريد الالكتروني
M C D MouradMourad, M C Dباحثدكتوراهm.mourad@ucl.ac.uk
محمد مختارMokhtar, Mohammed باحثدكتوراهmmokhtar2000@yahoo.com
M G TuckerTucker, M Gباحثدكتوراه 
E R BarneyBarney, E Rباحثدكتوراه 
R I SmithSmith, R Iباحثدكتوراه 
عبدالرحمن عبيد اليوبيAl-Youbia, Abdulrahman Obaidباحثدكتوراهaalyoubi@kau.edu.sa
سليمان ناصر باسهلBasahel, Suliman Naserباحثدكتوراهsbasahel@kau.edu.sa
M S.P ShafferShaffer, M S.Pباحثدكتوراه 
N T SkipperSkipper, N Tباحثدكتوراهn.skipper@ucl.ac.uk

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