Catalysts based on Ni/PrO2-ZrO2 mixtures (PrO2/ZrO2 mass ratio = 1, 4, 8; with Ni 20% of the total weight of catalyst) were synthesized by the one-step polymerization method. They were tested in Dry-Reforming of Biogas (1.5CH4:CO2), Oxidative Reforming of Biomethane (1.5CH4:CO2:0.25 O2), and Partial Oxidation Biomethane (2CH4:1O2). According to the characterization of the catalysts, the XRD results showed the stabilization of tetragonal ZrO2, by forming the PrO2-ZrO2 solid solution; also confirmed by XPS spectroscopy. By SBET analysis, it was found that the higher PrO2 content, increased the surface area (m2 g-1) of the catalysts. The in situ-DRX analyses (under reduction conditions with H2) showed that higher content of PrO2 promoted the decrease in the size of Niº crystallites of the catalysts. According to H2-TPR, the higher content of PrO2 favored the formation of NiO species strongly interacted with support. The catalytic tests showed that the PrO2-ZrO2 solid solution used as catalytic support strongly increased the production of Syngas over Ni-catalysts, and reduced the carbon deposits. The best catalyst was that with 8% PrO2 in the composition (Ni8PrZr), as it recorded the highest reactant conversion rates and the less amount of coke during the reactions. In situ characterization of the catalysts was carried out under reaction conditions (by X-ray absorption spectroscopy), and deactivation was explored. All the results of this research indicated that the use of PrO2-ZrO2 solid solution as catalytic support of Nickel is very promising to Syngas production from clean biomethane and biogas.