摘要
以NbC为前驱体,原位一步热处理制备了Nb_(2)O_(5)/NbC粉末光催化剂,研究了不同热处理温度(400,550,600℃)和保温时间(1,2,3 h)获得样品的光催化特性。使用XRD、SEM、HRTEM、XPS和UV-Vis、FT-IR对样品进行表征。结果表明,NbC氧化生成Nb_(2)O_(5)正交晶相,在400℃热处理1~3 h的样品中能明显观察到残留的NbC,形成了产物Nb_(2)O_(5)/NbC。随热处理温度的升高和保温时间的延长,NbC成分减少,可见光吸收逐渐降低。对样品在紫外可见光下降解亚甲基蓝的性能进行测试,发现400℃保温3 h制备的Nb_(2)O_(5)/NbC微晶材料光催化活性显著高于550和600℃制备的样品,这是由Nb_(2)O_(5)和NbC的协同作用引起的。光激发Nb_(2)O_(5)产生电子空穴对与亚甲基蓝发生反应,NbC杂化相的存在可提高光吸收和光生载流子的迁移率。碳的逸出导致微观孔洞结构,有利于吸附反应的进行,提高光降解效率。
Nb_(2)O_(5)/NbC photocatalysts are synthesized through in situ partial oxidation from NbC precursor by annealing in air.The photocatalytic activities are tested for samples prepared after 1-3 hours'heat treatment under 400℃,550℃and 600℃respectively.The as-prepared samples are characterized by XRD,SEM,HRTEM,XPS,UV-vis and FT-IR.XRD results indicate that NbC is oxidized into orthorhombic Nb_(2)O_(5) crystallites upon heating.Residual NbC apparently presents in samples prepared under 400℃.XPS reveals that the products are mainly composed of Nb_(2)O_(5),with more NbC oxidized under elevated temperatures.Irregular crystallites and aggregates are observed in SEM and HRTEM images.UV-vis light absorption spectra show the absorption edge of Nb_(2)O_(5)/NbC(410 nm).And the visible absorption decreases with less NbC component in the sample.Their photodegradation rates of methylene blue are tested.The best photodegradation rate is observed for Nb_(2)O_(5)/NbC microcomposites obtained from annealing under 400℃for 3 h.The enhanced photocatalytic activity comes from the synergetic effect from both Nb_(2)O_(5) and NbC.Nb_(2)O_(5) is photoreactive and provided photo-induced holes for the oxidation and mineralization of organics.NbC is able to facilitate the process through enhancing light absorption and carrier mobility.The escape of carbon during heating leads to mesoporous structure as well.Therefore,enhanced adsorption and photodegradation rates are achieved.
作者
马晓清
黄丽娜
MA Xiaoqing;HUANG Lina(School of Materials Engineering, Shanghai University of Engineering Science, Shanghai 201620, China)
出处
《功能材料》
CAS
CSCD
北大核心
2021年第11期11169-11176,共8页
Journal of Functional Materials
基金
国家自然科学基金资助项目(52002241)。
关键词
铌氧化物
一步法
原位制备
光催化
降解
niobium oxide
one-step method
in-situ preparation
photocatalysis
degradation
作者简介
通讯作者:马晓清(1992—),女,安徽阜阳人,硕士生导师,从事氧化物半导体光催化材料研究,E-mail:xqma@sues.edu.cn。
