The effect of support porosity on the selectivity of Pd-In/support catalysts in nitrate reduction

The influence of support porosity on the selectivity of home-made 5%Pd-2%In/support (support = SiO2, Al2O3, TiO2) catalysts in nitrate reduction was studied. The main final products of the reaction were N-2 and NH4 (+). Together with the decrease in pore diameter, an increase in ammonia concentration in the reaction mixture was observed. It is probably caused by slow diffusion of OH- ions from narrow pores to the solution.