Upconversion-agent induced improvement of g-C₃N₄ photocatalyst under visible light

Herein, we report the use of upconversion agents to modify graphite carbon nitride (g-C₃N₄) by direct thermal condensation of a mixture of ErCl₃·6H₂O and the supramolecular precursor cyanuric acid-melamine. We show the enhancement of g-C₃N₄ photoactivity after Er³⁺ doping by monitoring the photodegradation of Rhodamine B dye under visible light. The contribution of the upconversion agent is demonstrated by measurements using only a red laser. The Er³⁺ doping alters both the electronic and the chemical properties of g-C₃N₄. The Er³⁺ doping reduces emission intensity and lifetime, indicating the formation of new, nonradiative deactivation pathways, probably involving charge-transfer processes.