Pd@Pt core-shell designed nanoparticle catalysts have been shown to dramatically increase the activity and selectivity of the oxygen reduction reaction in fuel cells. Aberration corrected electron microscopy offers the spatial resolution and chemical sensitivity to unlock these structures at the atomic scale. Understanding the particle size, shape and the exact nature of the shell coverage (whether it is full, partial or whether the particle is alloyed) is vital to understanding their behaviour. This paves the way for even more effective catalyst designs. We present a semi-statistical investigation into the size, morphology and bimetallic content of various core-shell particle designs, pre- and post- fuel cell cycling, using high resolution HAADF STEM and EDX. In addition, careful quantitative analysis of our datasets will allow us to extract information, not only of the morphology, but also the thickness and coverage of the particle shells. We compare this with chemical findings about activity and selectivity to understand how shell coverage and content affect catalytic activity.
Materials by design for sustainable solutions in the energy, medical, transport, and engineering sectors
