Visible light active Ti³⁺ self-doped mesoporous TiO₂ photocatalyst with efficient photocatalytic performance for the degradation of chlorpyrifos

ABSTRACT

In the present research, Ti³⁺ self-doped TiO₂ photocatalyst (Ti³⁺-TiO₂) was fabricated through a facial in-situ NaBH₄ reduction approach. The as-prepared Ti³⁺-TiO₂ were characterised using FESEM-EDS, TEM, HRTEM, XRD, UV-DRS, PL, EIS, and BET methods. The photocatalytic performance of the Ti³⁺-TiO₂ was assessed through the degradation of chlorpyrifos (CPY) as an organophosphorus pesticide under visible LED light irradiation. The Ti³⁺-TiO₂ exhibited excellent photocatalytic degradation efficiency at initial CIP concentration = 1 mg L⁻¹, pH = 7, catalyst dosage = 0.2 g L⁻¹, and reaction time of 50 min with 97%, which is 4.62 times higher than that of pristine TiO₂. The extraordinarily boosted photocatalytic activity of Ti³⁺-TiO₂ can be attributed to mesoporous nanostructure, oxygen vacancy, and Ti³⁺ self-doping, which facilitates visible light harvesting and accelerates charge carrier separation and transport. In addition, Ti³⁺-TiO₂ shows outstanding mineralisation capability and recycling performance in degrading CPY. Coexisting water anions (NO₃⁻, Cl⁻, SO₄ ^2-, HCO₃⁻) and HA inhibited the degradation of CPY. Their inhibition effects of selected anions followed the order of HCO₃⁻ > SO₄ ^2-> NO₃⁻ > Cl⁻. Besides, a possible reaction mechanism of the photocatalytic process was recommended based on evidence from the radical scavenging test and photoelectrochemical measurements. The energy consumption value in this study was much less than that reported in other studies. Collectively, the findings show that Ti³⁺-TiO₂ photocatalyst has tremendous potential in solar photocatalytic degradation of refractory organic pollutants.

KEYWORDS:

• Visible-light-driven photocatalysis
• electron–hole pair
• Ti³⁺ self-doped TiO₂
• energy consumption

Acknowledgments

The present study was adopted from the project of Mansour Sarafraz at Aja University of Medical Sciences with 1400.213 project number. We are very grateful to Aja University of Medical Sciences for its financial and equipment support.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Aja University of Medical Sciences.