In conjunction with an industrial partner (Sasol Technology), it is proposed to apply INS to characterize a series of prototype Fischer-Tröpsch synthesis (FTS) catalysts that are active for the production of low molecular weight olefins. It has recently been reported that particular concentrations of certain modifiers can switch the FTS product slate from high molecular weight alkanes to high value low molecular weight alkenes. INS will be used to see how these modifiers perturb the hydrocarbonaceous overlayer that is thought to play a role in moderating how reagents are supplied to the catalyst’s active sites.