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

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.