Optical Characterization of Photocatalytic Copper Doped Thin Films of Anodized Titanium
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Date
2020
Authors
Rotich, Julia
Mwamburi, Mghendi
Njoroge, Walter
Maghanga, Christopher
Munyati, Onesmus
Hatwaambo, Sylvester
Journal Title
Journal ISSN
Volume Title
Publisher
IOP Publishing
Abstract
Titanium oxide is used in a myriad of applications such as in capacitors, insulation paints among
others. It is a prime candidate for water splitting due to its photocatalytic properties. In this work,
undoped TiO2 thin films were prepared by anodizing titanium foils cut into pieces measuring 60 mm
by 20 mm. The specimens were anodized in an electrolyte consisting of 0.5 M H2SO4 and 0.075% wt
HF at room temperature. The anodizing voltages ranged from 50 V to 100 V. Anion doping of copper
in as anodized TiO2was done electrochemically. The as anodized Ti foils were dipped in a 1 M Cu2SO4
solution. All samples were annealed at 450 °C for 3 h. Near-normal total reflectance was measured on
as anodized and copper pigmented samples in the solar(300–2500 nm)wavelength range. Spectrophotometric reflectance data was analyzed to obtain the absorption coefficient and using the same to
determine the band gap of the films. It was noted that the films exhibited reduced solar integrated
reflectance for TiO2 samples prepared at lower anodic voltages of 50, 60 and 70 V. The copper
pigmented, and annealed, TiO2 samples exhibited both direct and indirect energy band gaps in the
ranges, 3.38–3.86 and 2.50–2.74, respectively. Further, annealing and copper doping of the films lead
to increased absorption. The photocatalytic activity of the films was assessed by measuring the rate of
degradation of 10ppm methylene blue in UV light source. Copper doped TiO2 exhibited enhanced
photocatalytic performance in compared to pure TiO2. An increase in the anodization voltage caused
subsequent increase in photocatalytic activity of films with 70 V as the optimum voltage above which
photo degradation of methylene blue decreased.
Description
A research article published in Materials Research Express
Keywords
TiO2, Anodization, Doping, Photocatalysis, Band gap, Optical properties, Electro-deposition
Citation
Rotich, J., Mwamburi, M., Walter, N., Maghanga, C., Munyati, O., & Hatwaambo, S. (2020). Optical characterization of photocatalytic copper doped thin films of anodized titanium. Materials Research Express, 7(2), 025505.