Synthesis of stable and highly efficient Au@ZIF-8 for selective hydrogenation of nitrophenol.

A series of nanoparticles (NPs) with different Au content was successfully encapsulated into metal organic framework ZIF-8 with highly porous structure through room-temperature crystallization. X-ray diffraction, Fourier transform infrared spectroscopy, N adsorption and transmission electron microscopy were carried out to characterize the obtained Au@ZIF-8 heterogeneous catalytic material comprehensively. Au NPs were dispersed uniformly in the ZIF-8 and the Au NP diameter was 5-6 nm. The crystal structure of ZIF-8 was unchanged when compared with that before Au loading. It was found that the Au content plays an important role in the hydrogenation reaction. The obtained Au@ZIF-8 exhibited high hydrogenation activity to nitrophenol and excellent selectivity to aminophenol. The recyclability of the Au@ZIF-8 catalysts showed excellent catalytic performance and great stability in the recycling reaction.