Octahedral PtNi nanoparticles as ideal catalysts for the ORR.
Pre (catalysis) treatments determine the final catalytic activity.
Treatments under different pH environments induce substantial surface changes.
Compositional differences between nanoparticle bulk and its surface | solution interphase.
Species at the nanoparticles’ surface are pH-dependent and determine their reactivity.
Modifications prompted under operation conditions are crucial for catalyst reactivity.