Controlled organization of building blocks to prepare three-dimensional architecture of Pd-Ag aerogel as a high active electrocatalyst toward formic acid oxidation

Among self-assembled architectures, noble metal aerogels have emerged as state-of-the-art catalysts, and these unique architectures play a vital role in widespread applications. Until now, profuse ways have been introduced for the development and synthesis of noble metal aerogels, which suffer from long gelation time as well as complexity. In this work, a facile and efficient method is presented to create the Pd-Ag aerogel. This route offers advantages such as a surfactant-free route, short gelation time and a simple strategy. The Pd-Ag aerogel was prepared under controlled condition by using a galvanic displacement of sacrificial Ag nanoparticles with H2PdCl4 followed by supercritical CO2 drying. Porous three-dimensional architecture of Pd-Ag aerogel is confirmed by the TEM, FESEM, XRD, ICP-AES and N-2 isotherm. The resultant aerogel displays exceptional catalytic activity and durability toward electro-oxidation of formic acid on account of two vital reasons: 1) the unique architecture of resultant aerogel reflects exceptional advantages such as meso-and macroporous properties, and 2) the combination of Ag with Pd, leading to the acceleration in the oxidation of formic acid (synergistic effects).