Synthesis And Photocatalytic Properties Of Silver Phosphate

Photocatalyst, as a novel material applied in sustainable development, canunlimitedly use solar light for the decomposition of pollute substances, opening up aneffective way of environment treatment. As the most well known semiconductorphotocatalyst, titanium dioxide （TiO₂） has been widely used in various applicationsdue to its high oxidizing power, good chemical stability, non-toxicity and low cost.However, TiO₂only shows the photocatalytic ability under ultraviolet light irradiation,which limits the use of natural solar light to less than5%. The low-usage of solar lighthas greatly limited its further applications in environment treatment and new energydevelopment. Much R&D work has been done on photocatalytic materials which canbe used from the UV to the visible light region. These substances are called visiblelight-responsive photocatalysts. In2010, novel silver phosphate photocatalyst wasreported for its revolutionary oxidation property in decomposition of various organicdyes with a quantum yield of approximately90%under visible light irradiation, evenwith the microsized silver phosphate particles. However, it is still a big challenge tocontrol the size and morphology of silver phosphate and improve its photocatalyticdegradation ability. In addition, there is no report on the photocatalytic ability ofsilver phosphate in decomposition of NO_xgas, which is of great importance from apractical viewpoint because NO_xgas is one of the most common pollutants exhaustedfrom automobiles. In this thesis, a series of works related to the issues mentionedabove have been done and the following results were obtained:（1） A facile and novel ammonia-mediate method was developed for the synthesisof microsized cubic silver phosphate particles at low temperature. The particle sizecan be controlled by regulating the volume ratio of water and ethanol in the solution.The decomposition test of Rhodamine B showed that the average decomposition rateof cubic silver phosphate particles was4times higher than that of irregular ones.（2） Nano-sized silver phosphate particles, which showed high photocatalyticability for the oxidative decomposition of NO_xunder both visible light and UV lightirradiation, were synthesized by facile oleate-mediate method and citrate-mediate method. The NO_x decomposition ability of Ag3PO4nano-particles under both visiblelight irradiation and ultraviolet was superior to that of Degussa P25（TiO₂）.