MOx颗粒活性炭镀层粒子电极对苯酚的电催化降解特性

为研究半导体金属氧化物颗粒活性炭镀层粒子电极苯酚电催化性能,采用溶胶-凝胶、氧化还原与热分解方法,将TiO₂、MnO₂与SnO₂-Sb和SnO₂-Sb-Mn纳米金属氧化物镀层于AC(颗粒活性炭)表面,制备了催化型粒子电极,使用X-射线衍射(XRD)、扫描电镜(SEM)及循环伏安曲线(CV)对其物相组成、微观形貌及电催化活性进行表征与分析. 结果表明,这4类金属氧化物可以不同赋存状态存在于AC表面,粒子电极表面活性组分晶格尺寸分别为10.64、11.34、14.68及13.50 nm；催化型粒子电极电催化活性明显高于未负载AC,各粒子电极电催化活性顺序为SnO₂-Sb-Mn/AC>TiO₂/AC>SnO₂-Sb/AC>MnO₂/AC. 半导体金属氧化物镀层可提高填充床电极反应器苯酚废水的催化降解性能,废水苯酚及COD_Cr去除率显著提升,TiO₂/AC、MnO₂/AC、SnO₂-Sb/AC及SnO₂-Sb-Mn/AC粒子电极在电流密度为8.0 mA/cm2的条件下连续电解2.72 h,出水苯酚及COD_Cr去除率分别为87.1%、92.8%、90.4%、100.0%和92.5%、89.3%、88.7%、97.2%,高于AC粒子电极的84.2%和79.1%,并且可消除苯酚电催化反应中醌类物质积累. 

Electrocatalytic Performance for Phenol Degradation by a Composite Oxides MOx Carbon-Loaded Particle Electrode System

Electrocatalytic particle electrodes (i.e., MO_x/AC), including TiO₂/AC, MnO₂/AC, SnO₂-Sb/AC and SnO₂-Sb-Mn/AC, were prepared using sol-gel, redox and thermal decomposition methods. Their physical composition, micro morphology as well as electrocatalytic activity were investigated with X-ray diffraction (XRD), scanning electron microscope (SEM) and cyclic voltammetry (CV). The results indicated that Ti, Mn, Sn-Sb and Sn-Sb-Mn oxides were crystallized into different microstructures on the surface of the activated carbon (AC). The lattice sizes for TiO₂, MnO₂, SnO₂-Sb and SnO₂-Sb-Mn particles were 10.64,1.34,4.68 and 13.50 nm, respectively. Besides, the electrocatalytic activity of the virgin AC was improved with the presence of these nano semiconductor metal oxides. The electrocatalytic activities of the prepared MO_x/AC particle electrodes followed the order:SnO₂-Sb-Mn/AC>TiO₂/AC>SnO₂-Sb/AC>MnO₂/AC. Electrochemical oxidation of simulated phenolic wastewater was conducted to investigate phenol degradation properties with a MO_x/AC particle electrode system. The experimental results illustrated that a higher phenol and COD_Cr removal efficiency could be achieved after the implantation of the active components. The phenol and COD_Cr removal efficiencies with TiO₂/AC, MnO₂/AC, SnO₂-Sb/AC and SnO₂-Sb-Mn/AC particle electrode systems at current density 8.0 mA/cm2 with electrolysis time 2.72 h were 87.1% and 92.5%, 92.8% and 89.3%, 90.4% and 88.7%, and 100% and 97.2%, respectively, higher than those of AC, which were 84.2% and 79.1%. Furthermore, compared to virgin AC particle, MO_x/AC displayed a feature of no accumulation of benzoquinone, and is therefore considered to be a more environmentally compatible material. Our study confirmed the superior electrocatalytic performance of MO_x/AC as compared to virgin AC.