Photocatalytic activity of TiO₂ film containing Fe₂O₃ via plasma electrolytic oxidation

Abstract

This study investigated the photocatalytic activity of an Fe containing TiO 2 film produced in the FePO 4 electrolyte via the plasma electrolytic oxidation (PEO) method. For this purpose, the PEO process was carried out on titanium substrate under ac condition in two different alkaline electrolytes containing K 3 PO 4 and FePO 4 respectively. The structure, chemical composition and constituent phases of the PEO treated samples were analysed via SEM, X-ray photoelectron spectroscopy and X-ray diffraction. The optical properties of the samples were also examined by an ultraviolet-visible spectrophotometer. In terms of the photocatalytic activity judging from the decomposition of methylene blue under visible light illumination, the sample formed in the FePO 4 electrolyte was better than that in the K 3 PO 4 electrolyte due to the incorporation of an Fe compound that has a narrow band gap.

Photocatalytic behaviour of anodised titanium using different cathodes

“…The limiting values of nitrogen dioxide and monoxide, sulphur dioxide, particulate matter and others given by the European Council Directive 2008/50/EC on ambient air quality and cleaner air for Europe [3] are very low with the aim of improving air quality since traffic rates and industrial activities are increasing the pollution worldwide. A promising approach for fighting the problem of nitrogen oxides (NOx) is the photochemical conversion of these oxides to low concentrated nitrates thanks to heterogeneous photocatalytic oxidation using a photocatalyst [4][5][6]. Photocatalysis happens to be a potential answer to air purification, showing the ability of decomposition of organic compounds, sterilisation and self-cleaning among others [7].…”

“…However, the photocatalytic efficiency of this layer is generally negligible if not absent [14]. Yet, the oxide of this metal may show specific functions that find applications in fields such as biomedicine [6,15], photovoltaics [16], self-cleaning [17] and environmental purification [5][6][7][8]. Interestingly, titanium can be anodised in order to get a thicker and more performing TiO 2 layer, whose properties, including photocatalytic activity, depend on its structure, being more efficient if it is in crystalline form like anatase or rutile rather than in the amorphous one [18].…”

Plasma Electrolytic Oxidation of Titanium in Ni and Cu Hydroxide Suspensions towards Preparation of Electrocatalysts for Urea Oxidation

“…The reactivity of PEO layers can be easily influenced by changing the composition of the electrolytic bath, which is usually completed by adding soluble ions of dopants, i.e., Ni and Cu, to the electrolytic bath to prepare catalytic materials for CO to CO 2 oxidation [ 27 , 28 , 29 ], photoactive materials [ 26 , 30 , 31 ], biomaterials with possible antibacterial properties [ 32 , 33 ] or even catalysts for desulphurization and denitrification [ 34 ]. Other methods of doping of PEO layers are the impregnation of the coating with the soluble salt of the dopant, followed by drying and air annealing (500–1050 °C) [ 29 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 ], the hydrothermal route [ 43 , 44 ], electrodeposition [ 45 , 46 ], the sol-gel method [ 47 ], electroless plating [ 48 ], the solid-state reaction method [ 49 ], the alcohol-thermal method [ 50 ], reactive magnetron co-sputtering [ 51 ], dip coating [ 52 ] or even the coating of different materials with a TiO 2 paste [ 53 ].…”

A comparative study of characterisation of plasma electrolytic oxidation coatings on carbon steel prepared from aluminate and silicate electrolytes

“…In order to improve the wear and corrosion resistance, surface technologies have been used to prepare protective coatings on carbon steel, such as PVD [1], CVD [2], electroplating [3] and so on. Plasma electrolytic oxidation (PEO) is a relatively novel and promising surface technology [4][5][6]. It is an intricate combination of three electrical processes, including electrochemical process, plasma-chemical process and thermal diffusion process [7].…”