Biochar and bio-oil are produced simultaneously in one pyrolysis process

and they inevitably contact and may interact

influencing the composition of bio-oil and modifying the structure of biochar. In this sense

biochar is an inherent catalyst for pyrolysis. In this study

in order to investigate the influence of functionalities and pore structures of biochar on its capability for catalyzing the conversion of homologous volatiles in bio-oil

three char catalysts (600C

800C

and 800AC) produced

via

pyrolysis of poplar wood at 600 or 800 ℃ or activated at 800 ℃

were used for catalyzing pyrolysis of homologous poplar wood at 600 ℃

respectively. The results indicated that the 600C catalyst was more active than 800C and 800AC for catalyzing cracking of volatiles to form more gas (yield increase by 40.2%) and aromatization of volatiles to form more light or heavy phenolics

due to its abundant oxygen-containing functionalities acting as active sites. The developed pores of the 800AC showed no such catalytic effect but could trap some volatiles and allow their further conversion

via

sufficient aromatization. Nevertheless

the interaction with the volatiles consumed oxygen on 600C (de

crease by 50%)

enhancing the aromatic degree and increasing thermal stability. The dominance of deposition of carbonaceous material of a very aromatic nature over 800C and 800AC resulted in net weight gain and blocked micropores but formed additional macropores. The

in situ

diffuse reflectance infrared Fourier transform spectroscopy characterization of the catalytic pyrolysis indicated superior activity of 600C for removal of —OH

while conversion of the intermediates bearing C=O was enhanced over all the char catalysts.