Activated carbon supported rhodium(Rh/AC)catalysts with different amount of oxygen-containing functional groups were prepared by nitric acid treatment at definite temperatures.Thermal properties of Rh/AC catalysts with pre-and post-treatment were characterized by thermogravimetric analysis(TGA)and temperature programmed desorption(TPD).X-ray photoelectron spectroscopy(XPS)was used to characterize the change of surface oxygen-containing functional groups.These results indicate that the amount of oxygen-containing functional groups increased with the treatment temperatures.The product selectivity influenced by catalysts surface oxygen-containing functional groups was first investigated.The results show abundant functional groups not only improve the selectivity of n-heptanal,but also decrease the selectivity of hexane.These treated catalysts exhibited higher n/i(nor-mal to iso)ratio of heptanal.The Rh/AC catalyst treated at 80 ℃owned the highest n/i ratio of 2.3 due to maximum oxygen-con-taining functional groups,which is nearly double performance improvement than raw Rh/AC catalyst.Moreover,abundant func-tional groups on catalyst could suppress hydrogenation of hexene and the selectivity of hexane decreased from 4.9%of Rh/AC to 0.2%of Rh/AC-80.The result reveals the oxygen-containing functional groups on catalysts play an extremely role in improving the catalytic performance for heterogeneous hydroformylation,which provides a new a new viewpoint for heterogeneous hydrofromyla-tion.