Catalytic degradation of methylene blue by biosynthesized Au nanoparticles on titanium dioxide (Au@TiO2)

• DOI: 10.1007/s11356-022-22945-6
• Publication Date: 2022-09-15T11:03:58Z
• Authors: Yanan Wang; Tieliang Zhang; Yujie Zhao; Tong Lv; Wenjing Liu; Xiaowei Liu
• Keywords: Methylene Blue; Titanium; Metal Nanoparticles; Gold; Catalysis; 6. Clean water

Abstract Degradation of methylene blue is a critical procedure in its wastewater remediation, thus has inspired wide catalysis research with semiconductors such as Titanium dioxide (TiO2) and rare metals such as gold (Au). In this study we report bacterial cells assisting biosynthesis for Au@TiO2 as an efficient catalyst for the degradation of methylene blue. Multiple complementary characterization for bio-Aux@TiO2 evidenced the evenly distributed Au NPs on the bio-TiO2 layers. Meanwhile, bio-Au2@TiO2 displayed the superior catalytic activity in the degradation of methylene blue with the highest k value of 0.195 min-1. The origin of the catalytic activity was explored by the hydroxyl radical fluorescence quantitative analysis. In the bio-Au2@TiO2 catalytic system, Au NPs decreased the band gap energy of TiO2, increased charge separation between the excited (h+)–(e-) pairs, enabling the generation of a large amount of photogeneration hydroxyl radicals, resulting in an enhanced photocatalytic activity. Our microbial synthesized bio-TiO2 and bio-Aux@TiO2 study would be useful for developing green synthesis catalyst technologies.