摘要
采用溶剂热法制备了稀土Nd掺杂TiO_2-NTs/SnO_2-Sb电极,以苯酚作为典型有机物,考察了电极组成、结构与电极电催化效能的关系,实验结果表明,Nd的掺杂量对电极电催化性能有较大的影响,当前驱液中Nd/Sn原子摩尔百分比为3%时,电极的电催化活性最佳,对苯酚浓度及TOC的降解速率较空白电极(Nd0%)提高了60%及52%。利用SEM及XRD分析方法对所制备的电极进行了形貌及晶形结构的表征,并计算了电极表面SnO_2晶胞参数以及平均粒径,结果显示,适量地掺杂Nd元素后,电极表面更加致密,SnO_2平均粒径变小。通过XPS分析电极表面元素组成,并计算电极表面吸附氧含量,结果表明,由于Nd元素的存在,降低了涂层中晶格氧(O_(lat))的含量,减弱了电子的吸引作用,促使了Sn^(4+)周围电子云密度升高,从而电极表面Sn元素特征衍射峰表现为向低结合能方向偏移。与空白电极(Nd0%)相比,改性后的电极(Nd3%)涂层表面Sb含量下降,且吸附氧(O_(ads))含量上升,为空白电极的1.6倍。EPR测试结果进一步证实了改性后电极性能提高的机制,Nd元素的引入,增加了电极涂层表面氧空位的浓度,使得电极涂层表面各元素的化学环境发生改变。掺杂改性后,电极的析氧电位以及产羟基自由基能力均得以提升,从而促使电极催化活性大大增强。
Nd-doped TiO2-NTs/SnO2-Sb electrode was successfully fabricated by solvothermal synthesis approach.Phenol degradation test showed that the electrocatalytic property was affected by Nd doping content. Compare with the control electrode, the degradation rate of phenol and TOC were increased 60% and 52% on the one with Nd3%.The morphology and crystals structure of the catalytic coating were determined through SEM and XRD, the results showed that an optimum Nd content level could gain a denser surface structure and a smaller grain size than the control sample. The analysis of XPS indicated that introducing Nd could reduce the lattice oxygen（O（lat））, which was testified from the fact of lower banding energy of Sn displayed on Nd（3%）-doped electrode. In addition, the Sb on the electrode（Nd3%） surface reduced, and the adsorbed oxygen species（O（ads）） increased, which was 1.6 times as much as that on the control. The results from EPR further verified the mechanism of performance enhancement, introducing Nd could increase the concentration of oxygen vacancy and thus change chemical environment of the each element on the electrode surface, which greatly raised the oxygen evolution potential and strengthened the generation ability of ·OH to destroy organic matters.
作者
杨莉莎
刘俊峰
黄琳琳
郭嘉钰
冯玉杰
LOGAN Bruce
YANG Lisha;LIU Junfeng;HUANG Linlin;GUO Jiayu;FENG Yujie;LOGAN Bruce(State Key Laboratory of Urban Water Resource ＆ Environment,School of Environment,Harbin Institute of Technology,Harbin 150090,China;Department of Civil and Environmental Engineering,Pennsylvania State University,Pennsylvania State 16802,The United States of America)
出处
《环境工程学报》
CAS
CSCD
北大核心
2018年第8期2161-2169,共9页
Chinese Journal of Environmental Engineering
基金
城市水资源与水环境国家重点实验室(哈尔滨工业大学)自主课题(2018DX01)
黑龙江省科技攻关项目(WB10A401)
