Three-Dimensional Engineering of Nanoparticles To Fabricate a Pd-Au Aerogel as an Advanced Supportless Electrocatalyst for Low-Temperature Direct Ethanol Fuel Cells

Porous noble metal aerogels have emerged as an attractive target in the scientific community owing to their diverse applications. Nonetheless, their formation and development still face vital problems such as complexity and long gelation times. In this paper, we report a facile, one-pot, and short gelation time strategy for making a Pd-Au aerogel consisting of extended metal backbones by using a self-assembly process. The Pd-Au aerogel is achieved by reducing H2PdCl4 and HAuCl4 center dot 3H(2)O as metal precursors in the presence of sodium carbonate by using glyoxylic acid monohydrate as a reductant, followed by supercritical CO2 drying. In this process, the kinetics and the type of reaction product are controlled by sodium carbonate concentration. Characterization of the highly porous three-dimensional network is performed by utilizing field emission scanning electron microscopy, high-resolution transmission electron microscopy, selected area electron diffraction, transmission electron microscopy, nitrogen isotherm, X-ray diffraction, and inductively coupled plasma-atomic emission spectroscopy analyses. The resultant aerogel is applied as an advanced three-dimensional supportless catalyst for the oxidation reaction of ethanol in direct ethanol fuel cells at low temperatures (25 and 40 degrees C) in alkaline media and depicts an extraordinary electrocatalytic performance compared to that of Pd/C. The excellent efficiency of the three-dimensional architecture as an advanced electrocatalyst is ascribed to its amazing characteristics such as being supportless, macroporous, mesoporous, and microporous. In addition, the existence of a cometal (Au) in the structure of the Pd-Au aerogel can increase the chance for improving the adsorption of OHads onto the aerogel surface, thus helping to improve the oxidation process of ethanol. Undoubtedly, the resultant aerogel can be utilized as a promising anode component for direct ethanol fuel cells.