A green edge-hosted zinc single-site heterogeneous catalyst for superior Fenton-like activity

Abstract

Developing green heterogeneous catalysts with excellent Fenton-like activity is critical for water remediation technologies. However, current catalysts often rely on toxic transitional metals, and their catalytic performance is far from satisfactory as alternatives of homogeneous Fenton-like catalysts. In this study, a green catalyst based on Zn single-atom was prepared in an ammonium atmosphere using ZIF-8 as a precursor. Multiple characterization analyses provided evidence that abundant intrinsic defects due to the edge sites were created, leading to the formation of a thermally stable edge-hosted Zn-N₄ single-atom catalyst (ZnN₄-Edge). Density functional theory calculations revealed that the edge sites equipped the single-atom Zn with a super catalytic performance, which not only promoted decomposition of peroxide molecule (HSO₅^-) but also greatly lowered the activation barrier for ^•OH generation. Consequently, the as-prepared ZnN₄-Edge exhibited extremely high Fenton-like performance in oxidation and mineralization of phenol as a representative organic contaminant in a wide range of pH, realizing its quick detoxification. The atom-utilization efficiency of the ZnN₄-Edge was ~10⁴ higher than an equivalent amount of the control sample without edge sites (ZnN₄), and the turnover frequency was ~10³ times of the typical benchmark of homogeneous catalyst (Co²⁺). This study opens up a revolutionary way to rationally design and optimize heterogeneous catalysts to homogeneous catalytic performance for Fenton-like application.