One-step laser synthesis of TiO₂/Bi nanoparticles for enhanced photocatalytic performance

Abstract

Pulsed laser ablation in liquid (PLAL) has emerged as an effective technique for nanoparticle synthesis due to its simplicity and rapid processing capabilities. However, the fabrication of metal-modified nanoparticles often requires pre-prepared modified targets or additional synthesis steps. In this study, Bi-modified TiO₂ nanoparticles were synthesized through a novel one-step process using an Nd:YAG laser to ablate high-purity titanium plates in an aqueous bismuth nitrate solution. FESEM observations revealed a compact granular morphology composed of densely packed nanoparticles, while EDX analysis confirmed the presence of Ti, O, and Bi in the synthesized material. XRD and SAED analyses revealed structural changes while preserving the anatase TiO 2 phase after synthesis in Bi-containing media. TEM observations revealed reduced nanoparticle agglomeration following Bi modification. Photocatalytic performance was evaluated through methylene blue degradation, with varying bismuth nitrate concentrations used to optimize activity. The estimated band gap energy decreased with increasing Bi concentration, suggesting the formation of Bi-related electronic states that enhanced photocatalytic performance. Compared with pristine TiO₂, the sample prepared in 0.2 mM bismuth nitrate solution exhibited approximately 30% higher degradation efficiency. These findings demonstrate the potential of one-step PLAL as a simple and effective approach for producing Bi-modified TiO₂ nanoparticles for photocatalytic applications.