This study deals with the degradation of phenol over Pd–Fe/TiO2 catalysts at mild conditions in the presence of in situ generated H2O2 from oxygen and formic acid. This catalytic system demonstrated interesting ability to oxidize phenol by Fenton process in a one-pot reaction without the addition of ferrous ion. Lower Pd content catalysts, despite producing a higher hydrogen peroxide amount for bulk purposes, did not reach the same efficiency as the 5Pd–5Fe catalyst in phenol degradation. A close interaction between Pd and iron oxide species is necessary to obtain high active catalysts. These results highlight the advantage of in situ generation of H2O2, for oxidation reactions with respect to conventional Fenton process.