Electronegativity difference regulates the synergistic effect of dual-metal active sites for improved photodegradation of tetracycline

It is extremely necessary to reveal the synergistic effect of dual-active sites via the typical metallic atoms anchored on carbon nitride (CN) carrier, and the controllable synergistic effect is also a novel approach to regulate the neighboring coordination environment. Herein, a series of dual-active site photocatalysts are papered by doping Ag, Fe or Zn atoms due to their different electronegativity. Comprehensive characterizations demonstrate that embedding of Ag/Zn heteroatoms with significant electronegativity difference can regulate the synergistic effect of dual-active sites, which is beneficial for tailoring electronic structures, suppressing the recombination of photogenerated charges, and expanding the absorption range of visible light. Then, the Ag and Zn dual-metal atoms co-doped CN (Ag/Zn-CN) photocatalyst exhibits higher TC degradation rate (90.32 % at 90 min) and photoelectrochemical performance than the Ag/Fe-CN and Zn/Fe-CN, the first-order kinetic constant up to 0.041 min⁻¹ at t = 0 ∼ 50 min. This work provides a versatile avenue for the rational regulation of the coordination environment of dual-metal active site photocatalysts by embedding different neighboring atoms.