摘要
Herein,we report a novel ternary material comprised of Ag nanoparticles and carbon quantum dots(CDs),which are co-loaded using 2D Bi4Ti3O12(BIT)sheets.In this system,Ag can be applied as excited electron-hole pairs in the Bi4Ti3O12 by transferring the plasmonic energy from the metal to the semiconductor.The surface plasmon resonance of Ag can promote the electron transfer properties of the CDs,thereby improving the separation efficiency of the electron-hole pairs.Meanwhile,the CDs can act as an electron buffer to decrease the recombination rate of the electron hole.Moreover,CDs are prepared using a biomaterial,which can provide a chemical group to enhance the electron transfer and connection.The synergistic effects of CDs,Ag,and BIT enable the design of a photocatalytic application with a remarkably improved efficiency and operational stability.
众所周知,能源危机和环境污染是当前人们所面临的巨大难题和挑战,因此寻找或开发一种高新的技术解决上述难题尤为重要.近年来,基于半导体的光催化技术被广泛应用于能源制备和环境污染物去除领域,该技术通过直接转化太阳能为化学反应所需的能量来产生催化作用,使周围的氧气或水分子激发成活性物质,进而进行催化反应,且同时催化材料自身不受损耗,被认为是一种高效、安全的环境友好型技术.Bi_4Ti_3O_(12)是一种物理化学性质稳定、环境友好型的半导体材料,也是当前研究较多的一类铋系半导体光催化材料.然而,纯相的Bi_4Ti_3O_(12)纳米材料自身电子分离效率低且可见光响应范围窄,严重限制了其在光催化领域的应用.Ag纳米颗粒具有等离子共振效应,可以形成强的电场作用,从而增强光的利用和电子-空穴对的产生.碳点(CDs)是一类表面基团丰富、具有独特光物理性质的纳米级碳材料.碳点修饰的半导体光催化剂具有良好的稳定性和光催化活性.因此,制备Ag/CDs/Bi_4Ti_3O_(12)复合光催化剂可以有效扩宽Bi_4Ti_3O_(12)的光吸收范围,增强电子-空穴对的分离效率,从而提高光催化活性.本文利用竹子作为碳源,通过简单的水热法合成碳点,以熔盐法合成Bi_4Ti_3O_(12)纳米片,用简单的物理混合法将碳点修饰在Bi_4Ti_3O_(12)表面,再通过光沉积法将Ag^+还原在CDs/Bi_4Ti_3O_(12)的表面,从而制备出Ag/CDs/Bi_4Ti_3O_(12)复合光催化剂.以10mg/L的四环素水溶液作为目标污染物,测试光催化剂在可见光下对目标污染物的降解能力.采用X射线衍射(XRD)、傅里叶红外光谱(FT-IR)、透射电镜(TEM)、扫描电镜(SEM)、荧光光谱(PL)和光电流等表征方法分析了催化剂的结构特征、微观形貌和光电性质等.XRD分析表明Bi_4Ti_3O_(12)材料被成功合成,在CDs和Ag纳米颗粒进行修饰后未改变Bi_4Ti_3O_(12)的晶型结构.XPS和EDSmapp
基金
financially supported by the National Natural Science Foundation of China(U1510126,21676115)
the Natural Science Foundation of Jiangsu Provincial(BK20180884)~~
