Leveraging Commercial Silver Inks as Oxidation Reduction Reaction Catalysts in Alkaline Medium

Alkaline exchange membrane fuel cells (AEMFCs) development is impeded by the lack of low-cost processes for fabricating catalyst layers. One bottleneck lies in using large amounts of precious group metals during the layer deposition process by spray-painting. One possible solution would be to leverage inkjet printing technologies known for their full recovery of the printed material. Recent advances in printed electronics has led to the commercialization of silver (Ag) inks. We demonstrate the electrocatalytic properties (oxygen reduction reaction (ORR)) of Ag ink. Moreover, we show that a simple galvanic replacement reaction (GRR) on the Ag ink yields Ag_0.9M_0.1 (M = Pt or Pd) hollow nanoparticles. The resultant electrocatalyst demonstrated high activity for the ORR in alkaline medium. The Ag colloidal dispersion (the ink) reacted with a minute amount of platinum group metals precursors (PGMs). X-ray diffraction (XRD) and electron microscopy confirmed the hollow morphology and the formation of Pt or Pd-rich surfaces. The onset voltage for alkaline ORR activities follows the trend Ag_0.9Pt_0.1 > Ag_0.9Pd_0.1 > Ag. These experiments are a first step toward inkjet printing usage for fabricating catalytic layers.