High loads of rare earth single-atom lanthanum anchored carbon nitride with special double-layer coordination structure for efficient photocatalysis

A special two-layer coordination configuration anchored single-atom La (SALa) catalyst is synthesized to realize the effective separation of electrons in space and efficient active sites for the activation of O₂ to produce more active species. The special SALa microenvironment is obtained by a novel and facile reduction method that avoids the formation of rare earth oxides and the concentration of loaded SALa (10.34 wt%) exceeds that in most previous studies. The photodegradation test results show that antibiotics are almost completely removed within 30 min by SALa/CN. The first-order kinetic constant of SALa/CN (0.10661 min⁻¹) is approximately 9.81 times higher than that of 3DA-CN (0.01087 min⁻¹). SALa can be considered as a bridge to transfer electrons and •O₂⁻, ¹O₂ and h⁺ are the main active species to degrade tetracycline into some pollution-free small molecules. This work provides an efficient rare earth single-atom catalyst activity strategy possessing certain potential in practical applications.