Modern inorganic aerogels have drawn great attention in material science and renewable energy fields due to their exceptional physicochemical behavior, tremendous surface area, and large porosity. Despite many attempts, only a few strategies to produce metallic aerogels have been reported. Herein, a novel, surfactant-free, fast, and facile method is proposed to generate palladium aerogels. For the first time, carbon monoxide is used in the presence of HCl by a sol-gel procedure to create palladium aerogels assembled by nanochains. Moreover, palladium aerogels are constructed at low (0.05 M, Pd-AL), medium (0.5 M, Pd-AM), and high (1.0 M, Pd-AH) sol concentrations to assess their role in controlling morphology and electrocatalytic efficiency. The Pd-AL, Pd-AM, and Pd-AL display the porous three-dimensional networks with ultralow densities of 0.016, 0.019, and 0.024 g cm−3, respectively. Based on the comparative analysis, Pd-AL is the optimized form produced through the self-assembly process, with the highest electrocatalytic activity and durability. Pd-AL, Pd-AM, and Pd-AH showcased mass activities of 2.3, 1.7, and 1.3 A mg−1Pd, respectively. In addition, durability testing revealed that the specific activities of Pd-AL, Pd-AM, and Pd-AH toward formic acid oxidation after the 500th cycle retained 87%, 78%, and 65% of the initial mass activities, respectively. Undoubtedly, these self-supported 3D aerogels can be considered as superior candidates for diverse renewable energy applications.