Grant: Strategic Projects - Group

Anodization of titanium foils and thin films will be conducted using a two-electrode electrochemical cell with a platinum foil as cathode at a constant potential. A third electrode may have to be used as a reference electrode to eliminate noise effect when measuring the cell potential by potentiostat. Foils will be anodized at voltage ranging from 10 to 40 V, in a dilute [0.5-1 wt %] HF or KF aqueous solution at room temperature in order to create self-ordered titania nanotube arrays. Annealing at 480-600 °C in a hydrocarbon flame forms carbon-doped titania and promotes crystallinity of the nanotube arrays to rutile or anatase phase as well as narrowing the band gap energy. Nitrogen and sulfur doping of titania nanotube arrays will also be studied by addition of N and S bearing ions such as HNO3, KNO3, NaNO3, NH4NO3 or dimethyl sulfoxide [DMSO] into the anodization electrolyte solution. The doped nanotube arrays will be used as the photoanodes in photoelectron- chemical cells. Upon exposing to visible light, oxygen is evolved from the photoanode. Platinum electrode will be used as cathode at which hydrogen is evolved. The photoelectrolysis energy conversion efficiency (ECE) is expected to improve as the length of nanotube arrays is increased and their geometry improved. Alternatively, the titania nanotube arrays can be sensitized with a specific dye [ruthenium based dye]. When the titania nanotube electrode is illuminated, electrons are released and current passes in the circuit. The outcome of this research has huge potential and benefit for Canada. Once the efficiency of the hydrogen production is satisfactorily increased, the process can be linked to a fuel cell or a bio-fuel cell to produce energy in a distributed fashion. On the other hand, the produced doped nanotube arrays can be used in photovoltaic cells to produce electricity for small opto-electric devices and in photo-oxidation of organic compounds in water purification plants.