Cerium-based redox flow batteries (RFBs) such as Zn-Ce and V-Ce have received attention as attractive energy storage systems due to their high open-circuit cell voltages. To date, the most successful Ce-based RFBs have relied on expensive Pt-based positive electrodes. In this study, the use of more economical polyacrylonitrile (PAN)-based graphite felt (GF) containing tungsten oxide (WO₃) and/or tin oxide (SnO₂) nanocatalysts is examined for its electrochemical activity for the Ce(III)/Ce(IV) redox reaction in a series of half-cell experiments. Cyclic voltammetry is carried out at room temperature in a 0.05 M Ce(III) methanesulfonate +1.0 M methanesulfonic acid (MSA) electrolyte using a custom-made three-electrode cell. Among all modified GFs, those coated with a binary WO₃-SnO₂ mixture have exhibited superior electrocatalytic activity toward the Ce(III)/Ce(IV) reaction compared to the ones decorated with single oxides WO₃ or SnO₂. Presumably, this can be ascribed to the involvement of both metal oxides (WO₃ and SnO₂) in promoting electrolyte accessibility and improving the hydrophilicity of GF electrodes. SEM images indicate that the combination of WO₃ and SnO₂ promotes a more homogeneous dispersion over the graphite fiber surface and prevents clustering of the oxide particles that is more evident in the case of the single metal oxide catalysts.