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1990 (1)
1Author    VirendraK. Sharma, Werner Richarz, Surendra Sharma, Alarich WeissRequires cookie*
 Title    A NQR Study of y-alumina Containing Chemisorbed Cl 2  
 Abstract    Cl 2 was adsorbed at 370 and 870 K on commercially available y-alumina, with BET surface area of 180m 2 /g, after dehydration at 850 K. NQR measurements were carried out between 55 and 6 MHz. The sample containing Cl ? chemisorbed at 870 K showed the presence of a set of quite strong NQR signals with frequencies lower than 10.6 MHz, and another set of very weak NQR signals between 18.5 and 13.0 MHz. The stronger signals have been inferred as due to Al and have been assigned to Al in three distinct environments. The values of e 2 Qq/h and ^ determined for the signals are (1) 35.9 MHz, 0.53; (2) 35.7 MHz, 0.74; and (3) 35.3 MHz, 0.0 respectively. These values of e 2 Qq/h are found to be very high as compared to those estimated for 27 A1 at distorted octahedral and tetrahedral sites of the alumina, viz. 3.5 and 4.0 MHz respectively, from MAS-NMR. Therefore, chemisorption causes 27 A1 to exist in the surface region at sites with greater distortion than in the interior of the particles but much smaller than in the case of completely dehydrated samples for which no NQR signals could be observed. The weak signals have been tentatively attributed to 35 C1. The present results demonstrate that the NQR technique can be used in studies of chemically bound species on heterogenous catalysts. 
  Reference    Z. Naturforsch. 45a, 545—549 (1990); received August 22 1989 
  Published    1990 
  Keywords    Nuclear Quadrupole Resonance, Chemisorption, 35 C1, 27 A1, y-Alumina 
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 TEI-XML for    default:Reihe_A/45/ZNA-1990-45a-0545.pdf 
 Identifier    ZNA-1990-45a-0545 
 Volume    45