Struktur dan Kinerja Fotokatalitik Fe/TiO2 Nanotube (Fe/TNT) terhadap Diazinon dengan Pengaruh Variasi Persen Massa Ion Fe³+

Abstract

TiO₂ nanotubes are n-type semiconductor oxides that are extensively utilized photocatalysis applications. This study, TiO₂ nanotubes were modified with Fe3+ ion doping to reduce the band gap energy and increase photocatalytic activity diazinon compounds. The synthesis was carried out using the hydrothermal method by mixing TiO₂ micropowder and a 10 M NaOH solution, followed by the addition of Fe3+ dopant at varying concentrations of 0%, 0.1%, 0.3%, 1%, and 2%. The hydrothermal process was carried out in an autoclave (85% capacity) for 24 hours, with stirring occurring for 20 minutes at a time, every hour. The resulting Fe/TiO2 nanotube material was characterized using a range of analytical techniques, including XRD, SEM-EDX, TEM, FTIR, BET, and UV-Vis DRS. XRD characterization revealed that the sample with 1% Fe³⁺ doping exhibited a predominant anatase phase, while the other concentrations exhibited a mixture of anatase, sodium titanate, hydrogen titanate, and rutile phases. TEM characterization was utilized to ascertain the morphology of the nanotubes, which exhibited an outer diameter of 6.89 nm, an inner diameter of 2.82 nm, a wall thickness of 2.65 nm, and an overall size ranging from 16 to 32 nm. The Fe element composition was detected at concentrations of 0.3% (0.12%), 1% (1.54%), and 2% (1.90%), while it was not detected at 0% and 0.1%. FTIR spectrum indicates the presence of Fe–O bonds at a wavenumber of 593 cm⁻¹. The specific surface area of the material is in the range of 40–130 m²/g. UV-Vis DRS analysis demonstrates a decline in band gap energy from 3.2 eV to 2.8 eV with increasing Fe³⁺ dopant concentration. Photocatalytic activity testing against diazinon revealed that Fe/TiO2 nanotubes with 1% doping exhibited optimal performance, achieving a degradation efficiency of 86.5% after 90 minutes of irradiation and reaching a maximum of 90.41% after 150 minutes.