Abstract: Activated carbons, which were modified by chemical treatment in aqueous solutions of HNO₃, HCl, and H₂SO₄ or in gaseous N₂ and H₂, have been tested as catalysts in the reduction of nitrobenzene using hydrazine hydrate as hydrogen donor. Fourier transform infrared spectroscopy analysis and Boehm titration reveal that the chemical treatment leads to the formation of various oxygen functional groups on the surface of the activated carbon. These oxygen functional groups can induce the decomposition of hydrazine hydrate and influence the adsorption of nitrobenzene on the surface of the activated carbon. The catalytic activity is correlated to that of the oxygen functional groups, which suggests that an abundance of surface oxygen functional groups is favourable for this reaction. The activated carbon treated by hydrochloric acid had the largest amount of oxygen functional groups and exhibited the highest activity for nitrobenzene reduction to aniline.

Key words: activated carbon, hydrazine hydrate, nitrobenzene, hydrogenation