【作者】 郭伟；

【导师】 许春建；

【作者基本信息】 天津大学 ， 化学工程， 2019， 硕士

【摘要】 随着工业化进程日益深入,能源短缺、环境污染等问题逐渐暴露出来,全面、和谐的可持续发展成为全球关注的主题。光催化是解决当代能源和环境问题的理想手段,成为科研中最活跃的研究领域之一。光催化的核心是光催化剂,本文致力于对类石墨相氮化碳光催化剂进行一系列改性研究,包括类石墨相氮化碳与钨酸铋复合构建异质结和对类石墨相氮化碳进行钾铁共掺杂,具体研究内容如下:通过超声-化学吸附法成功制得拥有强吸附能力和高光催化活性的二维可见光激发Z型光催化剂钨酸铋/多孔类石墨相氮化碳（Bi₂WO₆/Porous-g-C₃N₄）。通过各种表征系统全面地研究了其物理化学性质。用Rh B脱色反应来研究其吸附和光催化能力。实验结果表明,Bi₂WO₆/Porous-g-C₃N₄-15同时拥有最强的吸附和光催化能力,分别为钨酸铋的2.55和3.31倍,为多孔类石墨相氮化碳的2.58和1.46倍。吸附能力增强与BET和Zeta电位表征结果相符。吸附不仅可以直接移除Rh B,且作为光降解过程的第一步,对光降解结果有着很大的影响。根据理论分析和陷阱实验结果,提出Z型载流子传输机理。在自产生的NH₃气体环境中成功制得拥有P型半导体特性和高光催化活性的钾铁共掺杂类石墨相氮化碳。通过各种表征系统全面地研究了其物理化学性质。自产生的还原性NH₃气体环境不仅可以使得类石墨相氮化碳的能带排列下移,也可以提高其光催化活性。光电流响应和莫特-肖特基曲线结果表明,该钾铁共掺杂类石墨相氮化碳拥有P型半导体特性,且拥有更高的光电流响应值。其光降解Rh B实验数据可用拟零级反应动力学模型拟合。光催化机理由陷阱实验来研究,结果表明其低能带结构和P型半导体特性拥有协同效应。更多还原

【Abstract】 With the thorough development of industrialization,dilemma such as energy depletion and environment pollution and so on,have been increasingly exposed.Sustainable development has became the common concern worldwide.Photocatalysis,considered as an ideal solution to cope with energy and environment issues,has became one of the most widely investigated scientific field.Photocatalyst is the core of photocatalysis.In this work,we have investigated the modification of g-C₃N₄,such as heterojunction construction with Bi₂WO₆and（K,Fe）co-doping.Details are listed as follows:A 2D/2D Z-scheme visible-light-driven Bi₂WO₆/Porous-g-C₃N₄with enhanced adsorption and photodegradation was successfully attained by an ultrasonication-assisted chemisorption method.Its physicochemical properties were systematically characterized.The adsorptive and photocatalytic activities were determined by Rh B decoloration experiments.The results show that Bi₂WO₆/Porous-g-C₃N₄-15 exhibits the highest adsorption capacity and photocatalytic activity,which is 2.55 and 3.31 times of that of Bi₂WO₆,and 2.58 and 1.46 times of that of Porous-g-C₃N₄.The adsorption enhancement was proved by BET and Zeta potential characterizations.The adsorption enhancement can not only help to remove Rh B directly,but also accelerate the initial step of photodegradation,which is of great importance in dyes removal.A Z-scheme mechanism was proposed,and particularly investigated through theoretical analyses and active species trapping experiments comparison on Bi₂WO₆and Bi₂WO₆/Porous-g-C₃N₄.P-type（K,Fe）co-doped g-C₃N₄was synthesized under self-generated NH₃atmosphere and displayed improved photocatalysis performances.Its physicochemical properties were systematically characterized.The reducing atmosphere,self-generated NH₃,strongly affects photocatalytic performances and causes a downshift of the band alignments.The photo-current response and Mott-Schottky plots show that the as-synthesized（K,Fe）co-doped g-C₃N₄is of P-type and has a boosted current density.Photocatalytic activity evaluation in Rh B solution could be well fitted by zero-order kinetic.Photocatalytic mechanism was investigated based on trapping experiments,suggesting a synergistic effect between low E_VBand p-type behaviors.更多还原