Catalytic hydrothermal conversion of cellulose over SnO2 and ZnO nanoparticle catalysts

The hydrothermal conversion of cellulose in the presence of nanometal oxide particles (SnO2 and ZnO) was investigated in this study. Both catalysts were synthesized hydrothermally and characterized using TEM, FESEM-EDX, X-ray diffraction spectroscopy and BET (Brunauer, Emmett and Teller) methods. In order to reveal the effect of nano-scale catalysts, experiments were conducted using bulk (non-nano) metal oxide and pure cellulose without any catalyst. The hydrothermal conversion experiments were carried out in a micro autoclave at 300, 400, 500, 600 °C and 1 h reaction time. The compositions of the gaseous products and the aqueous phase were determined with various analytical techniques (GC, ion chromatography, HPLC, UV–vis). Contribution of carbon containing products to the carbon mass balance was also represented. The results indicated both nano and bulk ZnO and SnO2 to have an effect on the water–gas shift reaction at varying temperatures. The water–gas shift reaction (WGS) proceeded fast at 300 °C in the presence of ZnO, while the rate of WGS was lower at 300 °C in the presence of SnO2. Nano ZnO led to improved hydrogen yield, while ethane and propane were formed as a result of side reactions in the presence of nano and bulk SnO2.