Enhanced Visible-Light-Induced Photocatalytic Activity in M(III)Salophen-Decorated TiO₂ Nanoparticles for Heterogeneous Degradation of Organic Dyes

Abstract

In this work, the construction of two heterojunction photocatalysts by coordinative anchoring of M(salophen)Cl complexes (M = Fe(III) and Mn(III)) to rutile TiO 2 through a silica−aminopyridine linker (SAPy) promotes the visible-light-assisted photodegradation of organic dyes. The degradation efficiency of both cationic rhodamine B (RhB) and anionic methyl orange (MO) dyes by Fe− and Mn−TiO 2 -based catalysts in the presence of H 2 O 2 under sunlight and low-wattage visible bulbs (12−18 W) is investigated. Anionic MO is more degradable than cationic RhB, and the Mn catalyst shows more activity than its Fe counterpart. Action spectra demonstrate the maximum apparent quantum efficiency (AQY) at 400−450 nm, confirming the visible-light-driven photocatalytic reaction. The enhanced photocatalytic activity might be attributed to the improved charge transfer in the heterojunction photocatalysts evidenced by photoluminescence (PL) and electrochemical impedance spectroscopy (EIS) analyses. A radical pathway for the photodegradation of dyes is postulated based on scavenging experiments and spectral data. This work provides new opportunities for constructing highly efficient catalysts for wastewater treatment.

Antimicrobial Activity against Fusarium oxysporum f. sp. dianthi of TiO2/ZnO Thin Films under UV Irradiation: Experimental and Theoretical Study

“…Furthermore, TiO 2 is considered harmless to the environment. , ZnO is another semiconductor commonly implemented in heterogeneous photocatalytic systems. , Both of them (TiO 2 and ZnO) are photocatalytically active only under UV irradiation due to their high band gap value. Various strategies have been implemented to improve photocatalytic activity (e.g., doping, , sensitization, , quantum dots, , heterostructures with other semiconductors with smaller band gap, , and anion vacancies). The heterostructures have the advantage that can improve the photocatalytic activity and reduce the charge recombination rates. , Also, Rajkumar et al reported that ZnO nanoparticles show activity against Bacillus sp., Escherichia coli, Staphylococcus aureus, Vibrio cholerae, Corynebacterum sp., and Salmonella sp., and the bacterial deactivation was associated with destruction of cellular walls by actions of the reactive oxygen spices (ROS) .…”

“… 24 , 25 Both of them (TiO 2 and ZnO) are photocatalytically active only under UV irradiation due to their high band gap value. Various strategies have been implemented to improve photocatalytic activity (e.g., doping, 26 , 27 sensitization, 28 , 29 quantum dots, 30 , 31 heterostructures with other semiconductors with smaller band gap, 32 , 33 and anion vacancies 34 ). The heterostructures have the advantage that can improve the photocatalytic activity and reduce the charge recombination rates.…”

Increasing the photocatalytic degradation rate of a rGO/PVA nanocomposite decorated with ZnO nanoparticles

“…[1][2][3] Pesticides, dyes, medicines, and even persistent organic pollutants have all been demonstrated to be eliminated successfully through the use of photocatalytic technologies. [4][5][6][7] Also, compared to other forms of treatment, photocatalytic technology has several benefits. A lowcost method is one that does not involve the use of chemicals or the creation of dangerous byproducts.…”

Congo red pigment weeding out from water media via RuO2@ZnO nanostructure

“…Dye pollution is one of the most pressing issues facing the industry. In fact, much of the synthetic dye does not stick, is lost in wastewater associated with manufacturing, and is usually discarded without treatment [1,2]. Organic dyes are one of the leading factors of pollutants in the water, which is generated by the wastewater discharges of several manufacturing sectors including textiles, plastics, dyeing, photography, printing, and tanning [3].…”