Constructing Cu-Mn bimetallic synergistic sites in 2D metal-organic framework nanosheets to induce polarized charge distribution: Electronic structure transformation and evaluation of Fenton-like performance

Abstract

Heterogeneous Fenton-like process based on H2O2 was an efficient method for the abatement of micropollutants in water. However, the mass transport resistance caused by the limited access between catalytic sites and target chemicals still restrict the decontamination efficiencies. Metal-organic frameworks (MOFs) with uniformed pores and anbundant metal sites shows great potentail in environmental remediation, Here, a novel two-dimensional nanosheet consisting of Cu and Mn bimetallic-oxygen clusters (CuMn-BDC, BDC refers to terephthalic acid organic ligand) was rationally designed and characterized. The introduction of second metal Mn changed the surface electronic distribution and accelerated the electron transfer of pristine Cu-based nanosheet, leading to improved catalytical acticities and removal effeciencies (kSA) for Sulfamethoxazole (SMX). The catalytic activity of CuMn-BDC obtained (5.76 × 10–4) was 3.95 times higher than that of Cu-BDC (1.46 × 10–4), demonstrating that the CuMn-BDC showed higher reaction rates than that of Cu-BDC when same amount of H2O2 was added. The interfacial micro-electric fields in bimetallic MOFs increased the interaction of organic pollutants and transfer the electron to activate H2O2. Several quenching experiments, electron paramagnetic resonance spectra and theoretical calculations were performed to study the reaction mechanism systematically. Further the powder was fabricated into membrane with higher water stablities. This study shed light on develop efficient 2D-MOFs catalyst for the abatement of micropollutants in water.