It can be deduced from this eqaution that for a graphitized structure (IV=0), the O+H/C =0.092, which represent a chemichal composition of C=91,5 mol.%, H+O=8.5 mol.%, which is not far away from that of a graphitic material  with some defectes bearing hetero atoms (H and O). To our  knowledge, no such remarkable relation is found in the literature for biomass char.

Conclusion