Volatile–char interactions during biomass pyrolysis: Cleavage of C–C bond in a β–5 lignin model dimer by amino-modified graphitized carbon nanotube

This study investigated the interactions between volatile and char during biomass pyrolysis at 400 °C, employing a β–5 lignin dimer and amino-modified graphitized carbon nanotube (CNT–NH 2 ) as their models, respectively. The results demonstrated that both –NH 2 and its carrier (CNT) facilitated the conversion of the β–5 dimer, which significantly increased from 9.7% (blank run), to 61.6% (with CNT), and to 96.6% (with CNT–NH 2 ). CNT mainly favored the breakage of C–O bond in the feedstock to produce dimers with a yield of 55.5%, while CNT–NH 2 promoted the cleavage of both C–O and C–C bonds to yield monomers with a yield up to 63.4%. Such significant changes in the pyrolysis behaviors of the β–5 lignin dimer after the introduction of CNT–NH 2 were considered to be mainly caused by hydrogen-bond formations between –NH 2 and the dimeric feedstock/products, in addition to the π–π stacking between CNT and aromatic rings.