Pulse electrodeposited Pd nanoclusters on graphene-based electrodes for proton exchange membrane fuel cells

This study describes a pulse electrodeposition approach for the synthesis of palladium (Pd) nanocatalysts supported on graphene oxide (GO) sheets and their electrocatalytic performance in a single stack of proton exchange membrane fuel cell (PEMFC). Star-like Pd clusters consisting of several nanotips are well deposited over the GO sheets, and the primary size of the cluster ranges from 100 to 150 nm. Cyclic voltammetry (CV) has been adopted to examine the catalytic activity of Pd catalysts in 1 M H2SO4, showing a reversible hydrogen adsorption/desorption. The presence of GO sheets is presumed to render multifunctional roles in facilitating the dispersion of metallic Pd clusters, ionic diffusion, and charge transfer. The PEMFC performance increases with an increase in cell temperature. The single cell delivers the maximal power density of ∼1.08 kW g−1 at 70 °C and exhibits the apparent activation energy of ∼27.5 kJ mol−1 within the temperature region of 40–70 °C, according to an estimation of Arrhenius plots.