화학공학소재연구정보센터
International Journal of Hydrogen Energy, Vol.41, No.47, 21936-21944, 2016
Sputtering processed tungsten catalysts for aqueous phase reforming of cellulose
In the present study we show that over some types of heterogeneous tungsten catalysts cellulose can be efficiently converted to hydrogen. Highly active for aqueous phase reforming of cellulose at the temperature of 260 degrees C are catalysts prepared by magnetron sputtering of tungsten coating on oxidized Si wafers with the thickness of metallic tungsten about 185-200 nm. The catalysts were characterized by X-ray diffraction, transmission electron microscopy, chemisorption of CO and N-2-adsorption. The TEM and XRD images have shown uniform morphology of deposited tungsten layers in the form of nano-columns, while the contents of metallic alpha- and beta-W phases in the films changed with the thickness of coating. Since in the most active catalysts the content of metastable beta-W phase is always high, we suggest that this phase is closely related to APR activity. In our study (at not optimized conditions) tungsten catalyst prepared by magnetron sputtering achieved turnover frequency for H-2 production of 18.1 min(-1), which was 11.3 times more active than Pt/C catalyst. Moreover, the platinum catalyst is strongly deactivated by nitrogen and sulphur containing compound (2-mercaptobenzothiazole). In contrast, the tungsten catalysts prepared by magnetron sputtering display stable performance, i.e. retain their original activity. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.