Unveiling the Synthesis of a Zirconium-Substituted Copper Bismuth Oxide Catalyst for Visible Light-Responsive Photocatalytic Degradation of Persistent Organic Dye

In recent years, scientists have been confronted with the formidable task of wastewater management due to the occurrence of intricate organic pollutants. In this study, we constructed the zirconium-substituted copper bismuth oxide (Zr_0.2Cu_0.8Bi₂O₄) through an easy hydrothermal method and effectively employed it to eliminate complex organic pollutants. The evaluation of the photocatalytic efficiency of the catalysts was conducted toward the degradation of rhodamine B (RhB) under visible light irradiation. According to the experimental results, the RhB dye had a degradation rate of 79.16% when a CuBi₂O₄ catalyst was utilized. In contrast, the degradation rate of the Zr_0.2Cu_0.8Bi₂O₄ catalyst escalated to 98.34% in 35 min. Comparably, the rate constant of 0.1041 min⁻¹ was observed for Zr_0.2Cu_0.8Bi₂O₄, approximately 2.35 times higher than that of pure CuBi₂O₄ (0.0443 min⁻¹), thereby confirming the photocatalytic efficacy of the Zr_0.2Cu_0.8Bi₂O₄ catalyst. The enhanced photocatalytic effectiveness of the Zr_0.2Cu_0.8Bi₂O₄ catalyst can be attributed to its augmented surface area (83.57 m²/g) compared to CuBi₂O₄ (76.67 m²/g) and lowered bandgap energy of Zr_0.2Cu_0.8Bi₂O₄ (1.62 eV) than CuBi₂O₄ (1.76 eV) resulting from the integration of Zr⁴⁺ ions into the fundamental structure of CuBi₂O₄. Furthermore, analyzing the effects of various reaction variables showed a strong correlation with the removal of RhB dye. One plausible explanation for the degradation of RhB is the production of O₂^•− and ^•OH radicals on the catalyst surface. The synthesized Zr_0.2Cu_0.8Bi₂O₄ catalyst has shown exceptional photostability after five consecutive cycles. This study introduces a pragmatic and cost-effective method for producing catalysts that are efficient in the treatment of wastewater.