Three-dimensional inorganic polymer of Pd aerogel as a highly active support-less anode catalyst toward formic acid oxidation

Abstract

Metallic aerogels as a novel class of three-dimensional inorganic polymers have attracted a lot of attentions in academic researches. In this manuscript, an efficient way for the production of Pd aerogel is presented. The proposed way includes advantages such as one-pot synthesis, being fast, simple and surfactant free. The Pd aerogel is successfully synthesized by the reduction of H2PdCl4 with sodium borohydride followed by supercritical drying with liquid carbon dioxide. The extraordinary 3D network with the large porosity of Pd aerogel is confirmed by using TEM, FESEM, XRD, EDS, FT-IR and nitrogen isotherm techniques. The extraordinary 3D polymer is used as a support-less anode catalyst for the oxidation of formic acid. Based on the obtained results, the mass activity of 3D nanonetwork was estimated to be 1791.4 mAmg−1Pd, which was 2.67 times higher compared to Pd/C (668.5 mAmg−1Pd) nanocatalyst. Moreover, the Pd/C indicated a positive shift in onset potential, lower ECSA, greater Ea, greater RCT as well as weaker stability in comparison to the resultant aerogel. The exceptional catalytic behavior of 3D nanonetwork toward oxidation of formic acid was seriously affected by unique properties such as large porosity, high surface area as well as self-supporting characteristic of 3D nanonetwork.