Nanoconfinement-induced high activity of ZIF-8 derived atomic Zn-N-C materials for fenton-like reactions

Abstract

Atomic Zn-N-C materials are synthesized by direct carbonization of ZIF-8, which maintains the rhombic dodecahedron morphology (RDM) with abundant nanopores. Zn-N-C-RDM shows enhanced catalytic activity with bisphenol A (BPA) as model pollutant and peroxydisulfate (PDS) as oxidant. Molecular dynamic (MD) calculations show that mean square displacement (MSD) of PDS, BPA, and H2O molecules in the nanotunnels decreases obviously with smaller pore size. Due to the confinement, the BPA (di = 1.0 nm) and PDS (di = 0.5 nm) can easily enter and confined in the cavities of Zn-N-C-RDM. PDS can be therefore activated more easily to degrade BPA due to their faster diffusion and shorter transfer routes. > 97 % degradation of BPA can therefore be achieved by Zn-N-C-RDM within 20 min. Quenching experiments, electron paramagnetic resonance (EPR) and open circuit potential (OCP) results indicate that O2•− radical dominate the degradation. According to the density functional theory (DFT) results, the binding sites of Zn-pyridinic N are the main active sites. This work provides new insights for improving activity in Fenton-like reactions in the field of environmental remediation.