Thermally stable porous bimetallic (NixPt1x) alloy mesocrystals within a carbon framework are produced via an aerosol-assisted process for high-performance catalysts for the oxygen reduction reaction (ORR) and hydrogenation. The porous NixPt1x alloy has a robust composite of alloy nanoparticles with an adjustable composition and a porous carbon skeleton. Porous Ni(x)Pt(1)x alloys exhibit high thermal stability, retaining their crystalline structure and morphology at 550 degrees C for 6 h, as observed in thermal treatment tests under various conditions (time, temperature, and atmosphere). The porous NixPt1x alloy as a catalyst for the hydrogenation of propylene has high conversion efficiency (>80%) and low activation energy (E-a < 20 kJ/mol) at >= 80 degrees C through the suitable control of the element composition and a pore structure. As a catalyst for the ORR, the catalytic activity of the porous NixPt1x alloy is superior to that of conventional Pt/C (0.115 mA) (0.853 mA/cm(Pt)(2) at 0.9 V/cm(Pt)(2)). This is attributed to the homogeneous alloying of the metal components (Ni and Pt) and the increased accessibility of the reactants to the catalyst, resulting from the unique morphology of the porous NixPt1x alloy, i.e., hierarchical structure with high porosity.