Pore-Confined Silver Nanoparticles in a Porphyrinic Metal–Organic Framework for Electrochemical Nitrite Detection

Silver nanoparticles (NPs) are installed into a porphyrinic zirconium-based metal–organic framework (Zr-MOF), NU-902, through a postsynthetic modification followed by an ion-exchange process. Both the framework-immobilized Ag(I) ions and partially reduced silver NPs confined within the nanopores of NU-902 with the size of around 3 nm are found in the obtained composite. As both the silver NPs and porphyrinic linkers of NU-902 are electrocatalysts for the oxidation of nitrite, the obtained nanocomposite can be applied for the electrochemical nitrite sensor, and the resulting sensing performance is significantly better than that of the pristine porphyrinic Zr-MOF.