Theory 41/Geometry & Scale/Nanocatalysis
Small Particles Are Surface
The claim
Catalytic activity per unit mass peaks at an intermediate particle size because surface-to-volume rises as size falls while surface energy rises faster.
01Mechanism
Smaller particles expose more atoms, but those atoms bind intermediates too strongly, so there is an optimum.
02Prediction
Activity should peak at an intermediate size.
03Refutation
Monotonic activity with size would remove the competing term.