Gold nanoparticles on mesoporous Cerium-Tin mixed oxide for aerobic oxidation of benzyl alcohol

In the era of sustainable chemistry the development of nanocatalysis has drawn special attention. Here we report the preparation of nanocrystalline, mesoporous cerium-tin oxide solid solutions and tested for selective oxidation of benzyl alcohol, cinnamyl alcohol, 4-methylbenzyl alcohol, 2-octanol, and geraniol using molecular oxygen as an oxidant. Among different mesoporous supports with Ce/Sn compositions (98/2, 95/5, 90/10 and 80/20, the highest activity was found for the Ce-Sn mixed oxide (Ce/Sn = 95/5) supported gold nanoparticles. The microkinetic study shows that there was no mass transfer limitation in three phase catalytic system. The supports and the corresponding gold catalysts were extensively characterized by N2 physisorption, XRD, H2-TPR, NH3-TPD, TEM, XPS, RAMAN and XAFS techniques. The nanocrystalline solid solution of CexSn1-xO2 was detected by XRD analysis. The presence of oxide vacancy was confirmed by XPS and RAMAN studies. The reducibility of Ce-Sn mixed oxide support increased upon gold deposition which was confirmed by H2-TPR techniques. The TPD study indicates the alteration of acid-basic sites of the CeO2 oxide upon incorporation of tin and gold nanoparticles. The cooperative role between the gold species and the ceria-tin support has been observed while correlating the catalytic activity results with the characterization studies.