A hybrid material based on the immobilization of H3PMo12O40 polyoxometalate nanoparticles (POM) was obtained by using an activated carbon aerogel (ACP-100Q2) matrix, and was tested as a potential electrode material for a supercapacitor cell. A chemical activation with KOH was carried out in the carbon aerogel matrix (ACP-100), obtaining a greater BET surface area (334g/cm2) and different electrochemical behavior (ACP-100Q2). Both matrices (ACP-100 and ACP-100Q2) were immersed in a 1.15mM POM solution in order to determine the role of the chemical activation procedure in the immobilization of POM nanoparticles. All materials were characterized by Attenuated Total Reflection (ATR) and nitrogen isotherms. For the electrochemical characterization, the synthesized materials were mixed with 10% of Teflon and 20% conducting carbon in weight ratio. Then, a film was made and a portion was pressed onto a stainless steel grid as current collector. Cyclic voltammetry in 3-electrode cells using a 0.5 M H2SO4 electrolyte was used to determine the electrochemical performance. The chemical activation of the aerogel matrix with KOH was the key factor to immobilize and disperse the POM nanoparticles, which improved the capacitance behavior making this material suitable for its application as supercapacitor electrode material.