【作者】 刘振；

【导师】 于涛； 张曙光；

【作者基本信息】 天津大学 ， 化学工程， 2019， 硕士

【摘要】 在本研究中,我们提出了一种针对g-C₃N₄的简单易行的碱性化方法,并将其应用于新的领域。我们通过将前驱体三聚氰胺与KCl混合研磨、煅烧的方法得到K⁺离子插层样品,然后再通过与不同浓度KOH溶液反应得到碱性化的样品。我们对材料在碱性化过程中的结构变化进行了表征,并进行光催化氧化As（Ⅲ）和光催化还原Cr（Ⅵ）的性能试验。在此基础上,对碱性化g-C₃N₄进行Pt沉积改性,通过光致还原法得到不同质量分数Pt沉积的样品,并进一步考察了材料的光催化还原Cr（Ⅵ）能力。利用XRD、XPS、FT-IR、SEM、UV-Vis DRS、PL等分析表征手段,对材料的物相结构、表面形貌、光学性质等方面进行了分析。实验结果表明,碱性化g-C₃N₄的光催化性能显著提升,其中10 mol/L KOH溶液处理的材料的光催化性能最佳,其原因为碱性化过程中破坏了g-C₃N₄材料的边缘结构,打破了原有材料的电子平衡,使材料更容易受光激发生成自由电子,K⁺离子的引入使材料的电子输运能力得到提升。再进行Pt沉积后,样品的光催化还原性能进一步提升,其中Pt沉积量为0.6%的样品的性能最佳,这主要得益于LSPR效应导致材料的光吸收能力增强与肖特基势垒导致的电子空穴快速分离。这部分研究提出一种可能的光催化机理,并拓展了g-C₃N₄在光催化处理难处理金属/非金属离子方面的应用。更多还原

【Abstract】 A new facile and efficient way was used to prepare alkalinized g-C₃N₄ which was applied in a new field.By calcining the mixture of KCl and melamine to obtain the g-C₃N₄ which K⁺doped into the in-plane structure,then the alkaline samples can be obtained by treating with different concentrations of KOH.The structural changes of the materials during alkalinization were characterized,and the performance tests of photo-oxidation of As（Ⅲ）and photo-reduction of Cr（Ⅵ）were carried out.On this basis,the alkaline g-C₃N₄ was modified by Pt deposition.The samples with different mass fractions of Pt deposition were obtained by photoreduction method,and the ability of photo-reduction of Cr（Ⅵ）was further investigated.XRD,XPS,FT-IR,SEM,UV-Vis DRS and PL were used to analyze the phase structure,surface morphology and optical properties of the materials.The experimental results showed that the photocatalytic performance of alkalinized g-C₃N₄ was significantly improved.Among them,10 mol/L KOH treatment has the best photocatalytic performance.The reason was that the edge structure of g-C₃N₄ material was destroyed during the alkalinization process,and the electronic balance of the original material was broken,which made the material easier to generate free electrons by light excitation.The K⁺ions doping improved the electronic transport ability of the material.After Pt deposition,the photocatalytic reduction performance of the sample was further improved,and the sample with 0.6%Pt deposition had the best performance,which was mainly due to the enhancement of the optical absorption ability of the material caused by LSPR effect and the rapid separation of electron holes caused by Schottky barrier.In this part,a possible photocatalytic mechanism was proposed,and the application of g-C₃N₄ in photocatalytic treatment of refractory metal/nonmetal ions was expanded.更多还原