Homogeneous RuCl2(PPh3)(3) and RhCl(PPh3)(3) complexes were heterogenized on amine functionalized MCM-41. The heterogeneous ruthenium and rhodium complexes were used for catalytic upgrading of bio-oil under mild conditions (50-90 degrees C). Both showed good activity in the hydrogenation of aldehydes and phenols with C=C side chains in bio-oil. The stability and properties of the bio-oil improved significantly. By comparison, the heterogenized rhodium catalyst was more effective than the ruthenium catalyst. Moreover, the catalysts still showed good activity after three reaction cycles. The results demonstrated that the utilization of heterogenized homogenous metal complexes was a promising treatment for upgrading bio-oil.