The effect of the steam activation of low-rank coal-based carbons under different conditions on catalytic NO reduction is examined. Oxygen surface functional groups are closely related to this catalytic activity. Because factors such as surface area make interpretation of the results difficult, it is necessary to study the role of the surface chemistry using samples with different chemical properties but of the same origin and with similar Brunauer-Emmett-Teller surface areas. Such materials, obtained by varying steam activation conditions over the same precursor, were tested in low-temperature selective catalytic reduction of NO with NH3 in order to study the influence of the presence of oxygen groups on the catalytic activity, avoiding as far as possible the effect of porosity.