Montmorillonite-stabilized gold nanoparticles for nitrophenol reduction

Two gold-based catalysts were obtained by Au chemical reduction of the HAuCl precursor. The resulting nanoparticles were stabilized and immobilized on montmorillonite (Mt) and montmorillonite-ceria (Mt/CeO). All prepared catalysts were active in 4-nitrophenol to aminophenol reduction at room temperature. Synergy between montmorillonite and ceria is postulated in such a way that the montmorillonite phase hinders particle growth either by influencing the nucleation behavior of gold or by increasing the number of nucleation sites and raising the overall dispersion. The role of the ceria support, on the other hand, may be associated with the 4-NP adsorption at the ceria-gold interface, stabilizing the reaction intermediate and hence lowering the activation barrier for the reduction of 4-NP to 4-AP