Mineralization and Self‐assembly of Gold Nanoparticles using Sulfur Amino Acid Modified Hierarchically Porous Metal‐Organic Frameworks

Abstract

AbstractIn this work, we modified the hierarchically porous metal‐organic frameworks (HP‐MOFs) HP‐UiO‐66 with sulfur‐containing amino acid cysteine and methionine, respectively. The cysteine or methionine modified HP‐MOFs, HP‐UiO‐66‐C and HP‐UiO‐66‐M, can be used for the adsorption and mineralization of Gold nanoparticles. Au nanoparticles will form in HP‐MOFs when the concentration of chloroauric acid is relatively low. Intriguingly, when the concentration of the chloroauric acid solution was increased to 5 mg ml−1, hexagonal gold micro flakes appeared in the system after adsorption by the HP‐UiO‐66‐C and HP‐UiO‐66‐M. Transmission electron microscope revealed that the hexagonal gold micro flakes are formed by the ordered self‐assembly of gold nanoparticles induced by the HP‐UiO‐66‐C and HP‐UiO‐66‐M. The obtained AuNP@HP‐UiO‐66‐C and AuNP@HP‐UiO‐66‐M can catalyze the reduction of 4‐NP. The apparent reaction rates constant of unit mass catalyst kcat are 0.0356 mg−1 min−1 and 0.0265 mg−1 min−1, respectively.