Metal-Doped Porous Titanium Dioxide Particles For Photocatalytic Degradation Of Emerging Pollutants And Hydrogen Evolution

Abstract

This research addresses critical global challenges in environmental protection and sustainable energy by synthesizing and characterizing multifunctional, metal-doped porous titanium dioxide (pTiO2) nanoparticles. The study’s objective was to develop an effective photocatalyst for dye degradation, hydrogen evolution, and antibacterial treatment. Porous TiO2 was successfully synthesized using a solvothermal method, followed by systematic optimization of the diethylenetriamine (DETA)/titanium isopropoxide (TIP) precursor ratio and annealing temperature. The optimal bare pTiO2 sample (50 µL DETA / 200 µL TIP, annealed at 400 °C) exhibited a pure anatase crystalline phase and a high BET surface area of 199.67 m²/g. This bare catalyst achieved an exceptional total removal efficiency of 98.28% for Methylene Blue (MB) dye in 90 minutes, comprising 49.97% dark adsorption and 48.31% photocatalytic degradation. To enhance its performance and multifunctionality, the optimized pTiO2 was doped with silver (Ag) up to 1 wt%. The resulting Ag-pTiO2 composite demonstrated superior catalytic activity across both key applications. In hydrogen evolution experiments via sodium borohydride (NaBH₄) hydrolysis, the 4 mg optimal dosage of 1% Ag-pTiO2 yielded the highest total hydrogen volume (31.3 mL in 20 minutes), surpassing the bare pTiO2 (25.0 mL) and the uncatalyzed reaction (25.63 mL). Furthermore, the Ag-pTiO2 exhibited markedly superior broad-spectrum antimicrobial efficacy compared to the bare material against both Staphylococcus aureus (Gram-positive) and Escherichia coli BL21 (Gram-negative). Under light activation, the Ag-pTiO2 achieved complete bacterial growth suppression for S. aureus at approximately 0.125 mg/mL. This enhanced activity is attributed to a synergistic mechanism where the silver dopant acts as an electron sink, minimizing electron-hole recombination and increasing the generation of lethal reactive oxygen species (ROS). By precisely tuning the precursor chemistry and silver dopant levels, this study provides a versatile platform for synthesizing high surface area pTiO2 that simultaneously addresses water purification, clean energy production, and pathogen control. These findings offer a scalable pathway for developing multifunctional nanomaterials capable of tackling complex, interlinked environmental and public health crises.