Highlights
Pt/Ni nanoalloys are synthesized using microwave-assisted polyol reduction.
The surface composition of nanoalloys is varied from Pt-rich to Ni-rich.
The reactivity-composition relationship of nanoalloys shows a volcano curve.
The highest reactivity in p-nitrophenol reduction is found with Pt:Ni ≈ 1:1.
The service life of nanoalloys is extended by affixing them on graphene sheets.