02153nas a2200265   4500008004100000022001400041245005700055210005600112260006900168300001200237490000800249520136900257653002001626653000801646653000801654653001501662653000801677100002401685700001301709700001701722700002201739700001901761700002101780856008601801       2008                        eng d  a0925-400500aEPR and DRS evidence for NO2 sensing in Al-doped ZnO0 aEPR and DRS evidence for NO2 sensing in Aldoped ZnO  aPO BOX 564, 1001 LAUSANNE, SWITZERLANDbELSEVIER SCIENCE SAcMAR  a668-6730 v1303 a<p>Zinc oxide (ZnO) is a well-known semiconducting multifunctional material wherein properties right from the morphology to gas sensitivity can be tailor-made by doping or surface modification. Aluminum (Al)-incorporated porous zinc oxide (AI:ZnO) exhibits good response towards NO2 at low-operating temperature. The NO2 gas concentration as low as 20 ppm exhibits S = 17% for 5 wt. % Al-incorporated ZnO. The NO2 response increases with operating temperature and concentration and reaches to its maximum at 300 degrees C without any interference from other gases such as SO3, HCl, LPG and alcohol. Physico-chemical characterization likes differential thermogravimetric analysis (TG-DTA) electron paramagnetic resonance (EPR) and diffused reflectance spectroscopy (DRS) have been used to understand the sensing behavior for pure and A]-incorporated ZnO. The TG-DTA depicts formation of ZnO phase at 287 degrees C. The EPR study reveals distinct variation for O- (g=2.003) and Zn interstitial (g = 1.98) defect sites in pure and Al:ZnO. The DRS studies elucidate signature of adsorbed NO, species in aluminium-incorporated zinc oxide indicating its tendency to adsorb these species even at low temperatures. This paper is an attempt to correlate the gas sensing behavior with the physico-chemical studies such as EPR and DRS. (c) 2007 Published by Elsevier B.V.</p>10aaluminum doping10aDRS10aEPR10aNO2 sensor10aZnO1 aNavale, Shalaka, C.1 aRavi, V.1 aSrinivas, D.1 aMulla, Imtiaz, S.1 aGosavi, S., W.1 aKulkarni, S., K.  uhttp://library.ncl.res.in/content/epr-and-drs-evidence-no2-sensing-al-doped-zno-001908nas a2200217   4500008004100000022001400041245009100055210006900146260005700215300001200272490000800284520113100292653002601423653000801449653001101457653004201468653002801510100001401538700001701552856012101569       2009                        eng d  a1011-372X00aSelective oxidation of benzyl alcohol over copper phthalocyanine immobilized on MCM-410 aSelective oxidation of benzyl alcohol over copper phthalocyanine  a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGERcMAR  a434-4420 v1283 a<p>Copper phthalocyanine (CuPc) complexes immobilized on ``neat'' and Ti(4+) and Al(3+) containing MCM-41 mimic the functionality of metalloenzymes. These novel materials catalyze the oxidation of benzyl alcohol to selectively benzaldehyde at moderate temperatures using peroxides and molecular oxygen as oxidant. Electron paramagnetic resonance and X-ray photoelectron spectroscopic studies revealed that the acidity of the support (MCM-41) influences the electronic structure of the immobilized CuPc. On acidic supports a part of copper in CuPc got reduced from a ``formal'' +2 to +1 oxidation state. This reduction of copper in its oxidation state on different supports decreased in the order: Al-MCM-41 (Bronsted and strong Lewis acid sites) &gt; MCM-41 (silanol sites) &gt; Ti-MCM-41 (weak Lewis acid sites). A linear variation in catalytic activity with the concentration of Cu(1+) ions in different catalyst samples was observed. The study reveals that by suitably modifying the acidic properties of the support one can, in principle, fine-tune the electronic and catalytic properties of the active oxidation sites.</p>10aCopper phthalocyanine10aEPR10aMCM-4110aSelective oxidation of benzyl alcohol10aUV-visible spectroscopy1 aHamza, A.1 aSrinivas, D.  uhttp://library.ncl.res.in/content/selective-oxidation-benzyl-alcohol-over-copper-phthalocyanine-immobilized-mcm-41-0