Band gap and photo charge carrier tailoring in zirconium doped carbon nitride using ZrCl₄-DMF-melamine for photocatalytic degradation of rhodamine B

초록

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.

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