【作者】 陆阳；

【导师】 罗永松；

【作者基本信息】 信阳师范学院 ， 理论物理， 2012， 硕士

【摘要】 近些年来,全球性环境污染及能源危机问题越来越严重,研发能高效降解有机污染物和利用太阳光实现光催化制氢的技术是解决环境污染和能源危机两大问题的有效途径。光催化技术是指采用无机半导体作为光催化剂,能够利用可见光照射激发半导体产生的光生电子和空穴,进行氧化还原降解有机污染物,把有机污染物分解为水、二氧化碳、氢气和无毒害的无机酸。因此本文致力于设计对可见光响应的光催化剂钒酸铋(BiVO4),采用水热法合成不同形貌的BiVO4颗粒,并对其进行表征；系统研究了其生长机理和不同的合成条件对光催化材料晶型结构与表面形貌的影响；以罗丹明B (RhB)溶液为目标降解物,考察了BiVO4可见光催化剂在模拟太阳光照射下的光催化性能及其对污染物的降解机理,主要研究工作和结论如下：(1)采用水热法合成了哑铃形BiVO4光催化剂。通过XRD、SEM、TEM和DRS对BiVO4的晶相结构、颗粒形貌、化学组成以及光吸收性质等进行了表征；通过控制水热时间获得不同时间段的BiVO4产品的形貌,得出了其“成核-溶解-再结晶”的生长机理。通过调节初始反应物物质的量的比和所添加模板剂的质量等条件,可控合成了不同形貌的BiVO4样品。以罗丹明B (RhB)溶液为目标降解物模拟污染源,研究了不同条件下哑铃形BiVO4晶体的光催化活性,结果表明只有在可见光照射下哑铃形BiVO4光催化剂才表现出较好的光催化效率并且优于TiO2(P25)的光催化效率。(2)采用水热法,在没有添加任何模板剂和表面活性剂的情况下合成了BiVO4核壳微球光催化剂。通过XRD、SEM、DRS和Raman等对BiVO4微球的晶相结构、颗粒形貌、化学组成、比表面积以及光吸收性质等进行了表征。结果显示BiVO4微球拥有较高的比表面积(13.092m2/g)。通过控制水热时间观察核壳结构的BiVO4微球的生长过程,得出BiVO4微球的形成是基于奥斯特瓦尔德熟化机理。以罗丹明B (RhB)溶液为目标降解物模拟污染源,研究了不同形貌的BiVO4微球的光催化性能,结果表明较薄球壳的BiVO4微球具有很强的光催化活性。更多还原

【Abstract】 Recently, the global environment pollution and energy crisis become more and more serious. The research and development of semiconductor photocatalysis with high utilization efficiency of solar energy to split water into hydrogen or degrade organic pollutant has become an available approach to settle the environment and energy issues. Photocatalysis is an advanced technology that employing inorganic semiconductors as photocatalysts, and using the photogenerated electrons and holes in photons excitated semiconductor, pollutants can be degraded by oxidization or reduction. After photocatalytic process, organic pollutants are decomposed into water, carbon dioxide and non-toxic inorganic acid. So we devote ourselves to design and development of new and efficient BiVVO4photocatalyst with visible-response and different morphologies by hydrothermal route. A series of BiVO4samples are synthesized and characterized. We systemally analyzed their formation mechanisms, studied the relationship between prepared conductions and the crystal phase and morphology of samples, investigate the photocatalytic activity under the mimetic visible-light irradiation by using RhB as target degradation, and discussed the degradation mechanism. The main research contents and results are given as follows:(1) Successfully synthesized the dumbbell-like BiVO4photocatalyst via a hydrothermal route. The crystal structures, morphologies, chemical composition and visible-light absorption of the obtained products were well-characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and diffuse reflectance spectroscopy (DRS). The different period morphologies of the dumbbell-like BiVO4samples were obtained by controlling the hydrothermal time, the results indicated that the nucleation and growth of the dumbbell-like samples were dominated by a’nucleation-dissolution-recrystallization’ growth mechanism. Moreover, BiVO4samples with various morphologies were fabricated by controlling the reaction concentration, the PH value and the kind of and the dose of surfactants. Rhodamine B (RhB) was selected as a target pollutant to evaluate the photocatalytic efficiency of BiVO4catalysts under different conditions, it is shown that the dumbbell-like BiVO4photocatalyst exhibit an excellent photocatalytic activity that better than TiO2(P25) in the photodegradation of RhB under visible light irradiation.(2) BiVO4core-in-hollow-shell spheres were synthesized by using a mild addictive-free hydrothermal treatment. The crystal structures, morphologies, chemical composition, visible-light absorption and specific surface area of the obtained products were well-characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS) and Brunauer-Emmett-Teller (BET). The ultrahigh BET specific surface area of ca.13.092m2/g is displayed for the BiVO4core-in-hollow-shell spheres. We observed the growth process of the prepared BiVO4samples by controlling the hydrothermal time, and the results proved that the nucleation and growth of the BiVO4core-in-hollow-shell spheres were based on ’Ostwald Ripening’mechanism. Rhodamine B (RhB) was selected as a target pollutant to evaluate the photocatalytic efficiency of different morphologies BiVO4catalysts, it is shown that the BiVO4core-in-hollow-shell spheres with thinner shell exhibit excellent photocatalytic activity in the photodegradation of RhB under visible light irradiation.更多还原