Table 1.

Comparison between Homogeneous and Heterogeneous Catalysis.

	Homogeneous	Heterogeneous
Active Centers	All atoms	Only surface atoms
Selectivity	High	Low
Mass Transfer Limitations	Very rare	Can be severe
Structure/Mechanism	Defined	Undefined
Catalyst Separation	Tedious/Expensive (extraction or distillation)	Easy
Applicability	Limited	Wide
Cost of Catalyst Losses	High	Low