Nitrogen-Doped\nPorous Carbon-ZnO Nanopolyhedra Derived from ZIF-8: New Materials\nfor Photoelectrochemical Biosensors

Abstract

Herein, novel photoactive\nmaterials, nitrogen-doped porous carbon-ZnO (NPC-ZnO) nanopolyhedra,\nwere prepared by direct carbonization of zeolitic imidazolate framework\n(ZIF)-8 nanopolyhedra in a nitrogen atmosphere. The morphology, structure,\nand photoelectrochemical (PEC) properties were characterized by scanning\nelectron microscopy, transmission electron microscopy, X-ray photoelectron\nspectroscopy, Raman spectroscopy, nitrogen adsorption–desorption\nmethod, and PEC methods. The results showed that the obtained NPC-ZnO\nnanopolyhedra had a rhombic dodecahedron morphology with uniform particle\nsize of about 100 nm and a high surface area of 609.2 m² g^–1. Under visible-light irradiation, the NPC-ZnO\nnanopolyhedra showed better PEC performance than ZnO nanorod and the\nZIF-8 nanopolyhedra in aqueous media with dissolved oxygen and ascorbic\nacid. Taking alkaline phosphatase (ALP) as a model, a NPC-ZnO nanopolyhedra-based\nPEC sensor was developed and showed good performance for ALP assay\nwith a wide linear response range from 2 to 1500 U L^–1 and a low detection limit of 1.7 U L^–1. Moreover,\nthe PEC sensor possessed acceptable selectivity, reproducibility,\nand stability. The prepared NPC-ZnO nanopolyhedra provide a new photoactive\nmaterial for the construction of PEC sensors and may have promising\napplications in PEC assay of heavy metal ions, organic pollutants,\nand biomolecules.