Depends on what type of catalyst you are talking about, for example, heterogenous catalyst, you can use vis spectrum to study the metal nanoparticles deposited on the oxide support. While FTIR is more useful here to study the surface of catalyst, ex. bronsted acidity
i very thank full .....if you share the specific literature ..... i am chemical engineer working the field of Catalytic conversion of the Essential oil....please help in this view also ,,