Synthesis and characterization of novel bio-Ca doped Bi4Ti3O12 with the investigation of rhodamine-B removal under solar irradiation

Abstract

This study presents a novel approach for synthesizing high-performance Bi₄Ti₃O₁₂ trilayer-doped bio-calcium derived from snail shells using the molten salt technique at 850 °C. Three catalysts were prepared with varying amounts of bio-calcium (Bi_(4−x)Ca_xTi₃O₁₂), where (x1 = 0.05, x 2 = 0.1, x3 = 0.15), it was observed that this activation led to an improvement in properties, the most important of which was an increase in the surface area and a reduction in the gap energy, resulting in excellent photocatalytic efficiency, particularly for biocatalysis with x3 = 0.15. The meticulous engineering of these catalysts gives rise to a synergistic effect, which facilitates efficient charge separation. Moreover, the introduction of bio-Ca led to an expansion in surface area, reaching 4.16, 5.42, and 6.03 m²/g for the bio-Ca/BTO1, bio-Ca/BTO2, and bio-Ca/BTO3, thereby augmenting the catalyst's capacity to absorb, stabilize and photodegradation of Rhodamine-B within a 30 min. Physical and chemical analyses were performed: XRD, FTIR, Raman analysis, BET, MEB/EDX. The bio-Ca/BTO3 photocatalyst’s unique structure enhances its performance and activity by stabilizing and degrading Rh-B on its surface, reducing band gaps, and producing electron–hole pairs. This increased vulnerability to photocatalytic reactions allows for a greater diversity of interactions. The ·OH radical was identified as the most active species in the Rh-B degradation mechanism. The biocatalyst demonstrated remarkable efficacy in degrading the Rh-B dye under visible light irradiation. To assess its stability, an additional eleven repeated simple cycles were conducted. This design offers a novel way to produce high-performance photocatalysts with, an environmentally friendly and sustainable approach.