Catalytic decomposition of tar using iron supported biochar

Iron supported biochar catalysts were used to decompose toluene, a model tar compound, over a temperature range of 600-900 degrees C. Toluene conversion and decomposition rates increased linearly with increasing temperature and catalyst loading from 600 to 700 degrees C. Relative to biochar alone, the iron supported catalysts lowered the activation energy by 47% and decreased the formation of benzene, an intermediate in toluene decomposition. At 800 degrees C for the 13 and 18.7 wt.% iron loaded catalyst, toluene conversion approached 100% and benzene selectivity (S-B) was zero, compared to an S-B of 0.025% and 0.35% for 10% iron and the biochar, respectively. Time on stream studies with the 13 wt.% iron biochar catalyst, over the course of four days, resulted in a mean toluene conversion of 91% and benzene selectivity of 0.02%, These results indicate that inexpensive iron impregnated biochar catalysts could potentially be used to catalytically decompose tar molecules in syngas generated via biomass gasification. (C) 2014 Elsevier B.V. All rights reserved.