Elucidating the roles of Ni ions and crosslinking heteroatoms in Ni3(BHT)2/2GO as electron shuttles for electrocatalytic oxidation of tetracycline hydrochloride

Abstract

As a hot candidate for marine pollution control, electrocatalytic oxidation strongly depends on the characteristics of anode materials. Even though emerging 2D metal-organic frameworks (2D-MOFs)/graphene oxide (GO) complex has satisfied the conductive and tunable requirements of anode, electrocatalytic efficiency still needs to be improved by maximizing the electron carriers or shuttles. Herein, we capitalized upon crosslinking heteroatoms as pointcut to adjust the electron distribution, mobility, and transfer orientation in 2D-MOFs/GO. As a result, Ni3(BHT)2/2GO (metal centers: Ni; crosslinking heteroatoms: S), which was much higher than materials with metal centers of Cu or crosslinking heteroatoms of N, achieved superior conductivity and 100% tetracycline hydrochloride removal within 12 min. In Ni3(BHT)2/2GO, Ni ions and S atoms cooperated as electron shutters rather than isolated active center and granted accelerated electron transfer from 2D-MOFs to GO layers. Furthermore, Ni sites and S crosslinking heteroatoms exhibited superior activity for ⋅O2− and ⋅OH generation, whereas 1O2 depended more on C and O substrates. All experiments, theory calculations, and application expanding approved the practice feasibility of 2D-MOFs/GO in electrocatalytic oxidation by adjusting crosslinking heteroatoms. All these results provided new perspectives on the micro-molecular regulation for improving electrocatalytic efficiency.