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Abstract:
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Semiconductor photocatalysis has received much attention during last
three decades as a promising solution for both energy generation and
environmental problems. Heterogeneous photocatalytic oxidation allows the
degradation of organic compounds into carbon dioxide and water in the
presence of a semiconductor catalyst and UV light source. The •OH radicals
formed during the photocatalytic processes are powerful oxidizing agents and
can mineralise a number of organic contaminants. Titanium dioxide (TiO2),
due to its chemical stability, non-toxicity and low cost represents one of the
most efficient photocatalyst. However, only the ultraviolet fraction of the solar
radiation is active in the photoexcitation processes using pure TiO2 and
although, TiO2 can treat a wide range of organic pollutants the effectiveness of
the process for pollution abatement is still low.
A more effective and efficient catalyst therefore must be formulated.
Doping of TiO2 was considered with the aim of improving photocatalytic
properties.
In this study TiO2 catalyst was prepared using the sol-gel method. Metal
and nonmetal doped TiO2 catalysts were prepared. The photoactivity of the
catalyst was evaluated by the photodegradation of different dyes and pesticides
in aqueous solution.
High photocatalytic degradation of all the pollutants was observed with
doped TiO2. Structural and optical properties of the catalysts were characterized
using XRD, BET surface area, UV-Vis. DRS, CHNS analysis, SEM, EDX, TEM,
XPS, FTIR and TG. All the catalysts showed the anatase phase. The presence of
dopants shifts the absorption of TiO2 into the visible region indicating the
possibility of using visible light for photocatalytic processes. |