Catalytic Properties and Recycling of NiFe2O4 Catalyst for Hydrogen Production by Supercritical Water Gasification of Eucalyptus Wood Chips

Nickel iron oxide (NiFe2O4) catalyst was prepared by the combustion reaction method and characterized by XRD, N(2)adsorption/desorption, thermogravimetric analysis (TG), and temperature programmed reduction (TPR). The catalyst presented a mixture of oxides, including the NiFe(2)O(4)spinel and specific surface area of 32.4 m(2)g(-1). The effect of NiFe(2)O(4)catalyst on the supercritical water gasification (SCWG) of eucalyptus wood chips was studied in a batch reactor at 450 and 500 degrees C without catalyst and with 1.0 g and 2.0 g of catalyst and 2.0 g of biomass for 60 min. In addition, the recyclability of the catalyst under the operating conditions was also tested using recovered and recalcined catalysts over three reaction cycles. The highest amount of H(2)was 25 mol% obtained at 450 degrees C, using 2 g of NiFe(2)O(4)catalyst. The H(2)mol% was enhanced by 45% when compared to the non-catalytic test, showing the catalytic activity of NiFe(2)O(4)catalyst in the WGS and the steam reforming reactions. After the third reaction cycle, the results of XRD demonstrated formation of coke which caused the deactivation of the NiFe(2)O(4)and consequently, a 13.6% reduction in H(2)mol% and a 5.6% reduction in biomass conversion.