To further understand the secondary reactions during biomass pyrolysis, this study employs the pyrolysis-gas chromatography/mass spectrometry detection technique to investigate interactions between volatiles and char at 400 degrees C using benzyl phenyl ether (BPE) and different graphitized carbon nanotubes (GCNT, CNT-COOH, CNT-OH, and CNT-NH2) as model compounds, separately. The results show the BPE conversion increases from 0.1% (blank run), to 49.2% (with GCNT), to 55.1% (with CNT-COOH), to 61.3% (with CNT-OH), and to 70.2% (with CNT-NH2), caused by pi-pi stacking of aromatic rings between BPE and carbon nanotubes as well as hydrogen-bond formation between BPE and heteroatoms in functional groups. Such kinds of interactions significantly promote the cleavage of C-alpha-O to mainly form phenol and toluene. In the case of CNT-NH2, the breakage of C-aryl-O is also facilitated by the synergistic effect of hydrogen-bond and aromatic-hydrogen interactions.