Novel CoAl-LDH/g-C3N4/RGO ternary heterojunction with notable 2D/2D/2D configuration for highly efficient visible-light-induced photocatalytic elimination of dye and antibiotic pollutants

In this study, we fabricate a novel ternary heterojunction comprising CoAl-layered double hydroxide, g-C3N4, and reduced graphene oxide (LDH/CN/RGO) with a notable 2D/2D/2D configuration using a simple one-step hydrothermal method. The visible-light-induced LDH/CN/RGO ternary heterojunctions displayed significantly enhanced photocatalytic performance towards the degradation of aqueous Congo red (CR, dye) and tetracycline (TC, antibiotic) contaminants, which is far superior to that observed for pristine CN (base material), LDH, P25 (reference), and binary CN/RGO and LDH/CN heterojunctions. In particular, the LDH/CN/RGO ternary heterojunction with RGO and LDH contents of 1 wt.% and 15 wt.%, respectively, exhibited the highest degradation activity among all the fabricated catalysts, and it also displayed exceptional stability during recycling experiments. The significant enhancement in the photocatalytic performance and good stability of existing LDH/CN/RGO ternary heterojunctions were primarily attributed to the large intimate interfacial contact between constituent CN, LDH, and RGO prompted by their exceptional 2D/2D/2D arrangement, which accelerates the interfacial charge-transfer processes to effectively hinder the recombination of photoexcited charge carriers. The present study provides new insights into the rational design and fabrication of novel g-C3N4-based 2D/2D/2D layered ternary heterojunctions as high-performance photocatalysts, and promotes their application in addressing diverse energy and environmental issues.