Band gap and photo charge carrier tailoring in zirconium doped carbon nitride using ZrCl4–DMF–melamine for photocatalytic degradation of rhodamine B†
Abstract
Improving the performance of carbon nitride (CN) photocatalysts in photocatalytic degradation applications involves optimizing their morphology, electronic properties, and optical characteristics. Zirconium-doped carbon nitride (Zr-doped CN) photocatalysts were synthesized using dimethylformamide (DMF) as a solvent to facilitate the formation of complex molecular structures for effective metal doping. By varying the concentration of the zirconium tetrachloride (ZrCl4) precursor between 1 and 3 mmol, we observed significant enhancements in photocatalytic activity. Notably, controlling the ZrCl4 concentration below 3 mmol prevented the formation of zirconium oxide phases, which could otherwise negatively affect the photocatalytic performance. Zr incorporation led to the morphological transformation of CN from a bulk structure into a hierarchical porous structure, increasing the surface area to 135 m2 g−1. Additionally, Zr doping changed the band energy and electronic properties, creating an optimal energy level for generating oxygen radicals in the photocatalytic water-splitting processes. The photocatalytic degradation of rhodamine B showed that the Zr-doped CN photocatalysts achieved 4.5-fold better performance than undoped CN. Moreover, a small amount of ethylenediaminetetraacetic acid (EDTA) significantly enhanced the photocatalytic efficiency of Zr-doped CN compared to that of undoped CN. These results indicate that combining Zr-doped CN with other materials to create Z-scheme or S-scheme structures could further enhance its performance, thus emphasizing the potential of increasing photocatalytic efficiency by optimizing energy band structures and forming heterostructured photocatalysts.