In this work, Pt based mono and bimetallic catalysts were tested under conditions of tri-reforming (TR). All the catalysts contained 25% of CeO2 and a metal loading of 2.5 or 5.0% (wt%). The bimetallic catalysts contained 2.5% Pt and 2.5% of Me, where Me = Ni, Co, Mo, Pd, Fe, Re, Y, Cu or Zn. For all the experiments, a synthetic biogas which consisted of 60% CH4 and 40% CO2 (vol.) was mixed with water, S/C = 1.0, and oxygen, O2/CH4 = 0.25, and fed to a fixed bed reactor (FBR) system or a microreactor. The 2.5Pt catalyst was used in order to compare the performance of each reaction system. The tests were performed at reaction temperatures between 700 and 800 °C, and at volume hourly space velocities (VHSV) between 100 LN/(h gcat) and 200 LN/(h gcat) for the FBR system and between 1000 LN/(h gcat) and 2000 LN/(h gcat) for the microreactor, at atmospheric pressure. Then, all catalysts were deposited into microchannel reactors and tested at a constant VHSV of 2000 LN/(h gcat) and reaction temperatures between 700 and 800 °C. Catalysts under investigation were characterized applying the following techniques: inductively coupled plasma optical emission spectroscopy (ICP-OES), N2 Physisorption, Temperature Programmed Reduction (TPR), CO chemisorption, Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). The microreactor was identified as the most efficient and promising reaction system, and the 2.5(Pt–Pd) catalyst as the bimetallic formulation with the highest activity. Therefore its activity and stability was compared with the reference 5.0Pt catalyst at 700 °C and VHSV of 2000 LN/(h gcat) for more than 100 h. Although slightly lower activity was measured operating with the 2.5(Pt–Pd) catalyst, a significant reduction of the Pt content compared to the reference 5.0Pt catalyst was achieved through the incorporation of Pd.