Effect of different crystalline phase of ZnO/Cu nanocatalysts on cellulose pyrolysis conversion to specific chemical compounds

Abstract

With an appropriate treatment, cellulose, as one of the main constituents of biomass, is a rich source of chemicals and fuels. Pyrolysis is a method whereby bio-oils can be formed at moderate temperatures and with the addition of a catalyst the composition of the bio-oil can be enhanced. Nanostructured ZnO is a mild catalyst for the pyrolysis of cellulose to bio-oils and with the addition of copper to the structure of ZnO the catalytic properties can be improved. The pyrolytic degradation of cellulose over ZnO/Cu doped nanocatalysts has been studied over the temperature range 400–800 °C with calculation of kinetic parameters. The results showed that with ZnO/2% Cu and ZnO/7% Cu, which had been heat-treated at 1000 °C, the yields significantly increased at 600 and 700 °C and the main components were aldehydes. In contrast, ZnO/Cu nanocatalysts prepared at 200 °C mostly generated ketones. The increasing amount of copper increased or decreased the content of some components at specific temperatures. The results demonstrated that ZnO/Cu nanocatalysts with different proportions of copper prepared and heat-treated at different temperatures affected the composition of the bio-oil.