Three-dimensional catalyst systems from expanded graphite and metal nanoparticles for electrocatalytic oxidation of liquid fuels.

Cheap and high-performance electrocatalysts are required for fuel cells. Herein, we present the application of three-dimensional (3D) catalyst systems for electrocatalytic oxidation of formic acid and methanol. These systems consist of cost-effective boron-doped expanded graphite (B-EG) as the support and palladium nanoparticles (NPs) or platinum/palladium bimetal NPs as the catalysts. The characterization of these 3D catalyst systems using scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray, and electrochemical techniques reveals that stable and efficient electrocatalytic methanol oxidation, achieved in a 3D catalyst system of B-EG and PdPt bimetal NPs (with a mass ratio of 1 : 1), is due to its big surface area, high conductivity, and an enhanced amount of exposed active sites from bimetal NPs. This price-reduced, stable, and efficient 3D catalyst system is thus promising to be employed for a large scale production of industrial direct methanol fuel cells.