Tuning the morphology of Pd aerogels for advanced electrocatalysis of formic acid

Abstract

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.