Noble aerogel goes catalytic

A new aerogel nanomaterial that reduces the amount of noble metals, such as platinum or palladium, needed to make fuel cells should reduce the cost of such devices making them more commercially viable according to researchers in the USA and China. The aerogel could also improve efficiency.

Chengzhou Zhu, Qiurong Shi, Shaofang Fu, Junhua Song, Dan Du, and Yuehe Lin of the Department of Mechanical and Materials Engineering, at Washington State University, Pullman and Haibing Xia of the State Key Laboratory of Crystal Materials, Shandong University, Jinan, have developed a rapid synthesis of aerogels that avoids the need for noble metals. The materials could find use in hydrogen-powered fuel cells as a novel component of this promising environmentally friendly energy solution for the generation of electricity.

Aerogels are solids that are certainly worthy of their colloquial name of solid smoke in that they are 92 percent air by volume. They are powerful insulators and have found applications in diving wet suits, firefighting equipment and protective clothing, windows, in paints and as fuel cell catalysts. In this latter application it is the vast surface area per unit volume and high porosity that make the materials useful as catalytic components. The Washington State team has now created a series of bimetallic aerogels, that combine the relatively inexpensive transition metal copper with the precious noble metal which is needed in a smaller quantity in their aerogels.

The team made the bimetallic aerogel system using their one-step, high-temperature reduction method to first create a hydrogel exploiting enhanced gelation kinetics. The hydrogel is, to all intents and purposes, the liquid-filled form of the aerogel. The liquid component can subsequently be removed by careful drying to leave behind the seemingly delicate three-dimensional network of the aerogel. The novel synthesis has reduced the standard manufacturing time of a hydrogel from three days to just six hours.

"This will be a great advantage for large scale production," explains WSU's Zhu. The research was undertaken as part of WSU's Grand Challenges, a suite of research initiatives aimed at large societal issues. It is particularly relevant to the challenge of sustainable resources and its theme of energy. "The resultant PdCu aerogel with ultrathin nanowire networks exhibits excellent electrocatalytic performance toward ethanol oxidation, holding promise in fuel-cell applications," the team reports in the journal Advanced Materials [Zhu, et al., Adv. Mater. (2016) DOI: 10.1002/adma.201602546]

David Bradley blogs at Sciencebase Science Blog and tweets @sciencebase, he is author of the popular science book "Deceived Wisdom".