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用电化学方法制备Ag@AgBr/Ni表面等离子体薄膜光催化剂。对薄膜的表面形貌、晶相结构、光吸收特性进行了表征,用罗丹明B(RhB)作为模拟污染物对薄膜的光催化活性和稳定性进行了测定,探索了薄膜光催化降解机理。结果表明:Ag@AgBr/Ni的优化制备工艺为:电解液中NaBr和(NH_4)_3PO_4的浓度分别为0.3和1 mol/L,pH值为8.0,电解电流密度为2.5mA/cm~2,时间为18min,并在140℃后处理1 h。优化工艺下制备的Ag@AgBr/Ni薄膜表面是由附着少量Ag粒子的AgBr纳米晶构成。薄膜表现出明显的表面等离子共振效应、优异的光催化活性和良好的稳定性:可见光辐照15 min,薄膜光催化RhB的降解率(81.0%)是Ag_3PO_4/Ni薄膜的6倍,是P25 TiO_2/ITO薄膜的14倍;光照射1 h对RhB的降解率为99.5%,循环使用4次后的降解率仍为91.6%。薄膜的高光催化活性是由AgBr晶体在(111)晶面产生择优取向和薄膜表面纳米Ag发生等离子体共振效应引起的。讨论了可见光下薄膜光催化降解RhB的反应机理。
Preparation of Ag @ AgBr / Ni Surface Plasmon Thin Film Photocatalysts by Electrochemical Methods. The surface morphology, crystal phase structure and optical absorption properties of the films were characterized. The photocatalytic activity and stability of the films were determined by rhodamine B (RhB) as simulated pollutants. The photocatalytic degradation mechanism of the films was explored. The results show that the optimized preparation process of Ag @ AgBr / Ni is as follows: the concentrations of NaBr and (NH_4) _3PO_4 in electrolyte are respectively 0.3 and 1 mol / L, the pH value is 8.0, the electrolysis current density is 2.5mA / cm ~ 2, The time was 18 min and was post-treated at 140 ° C for 1 h. The surface of Ag @ AgBr / Ni thin films prepared by the optimized process is composed of AgBr nanocrystals with a small amount of Ag particles attached. The film showed obvious surface plasmon resonance effect, excellent photocatalytic activity and good stability: the visible light irradiation for 15 min, the degradation rate of RhB film (81.0%) was 6 times that of Ag_3PO_4 / Ni film, P25 TiO_2 / ITO film 14 times; 1 hour after light irradiation, the degradation rate of RhB was 99.5%, and the degradation rate was 91.6% after 4 times of recycling. The high photocatalytic activity of the film is caused by the preferred orientation of the AgBr crystal on the (111) crystal plane and the plasmon resonance effect of the nano-Ag on the film surface. The reaction mechanism of photocatalytic degradation of RhB under visible light was discussed.