%0 Journal Article
%T <br>
%A 尹振
%A 李建新
%A 杨映
%A 王虹
%A 田文杰
%J 物理化学学报
%D 2015
%R 10.3866/PKU.WHXB201506171
%X 利用乳液法制备出MnOx纳米颗粒,将其负载于微孔管式钛膜制得MnOx负载钛基电催化膜(MnOx/Ti).运用X射线衍射(XRD)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)、循环伏安法(CV)和计时电流法(CA)等表征方法系统考察了不同焙烧温度下MnOx晶型结构、MnOx/Ti催化膜电化学性能以及催化氧化苯甲醇的变化规律.结果表明:随着焙烧温度的升高, MnOx的晶型由初始的Birnessite-MnO2逐渐转变为K0.27MnO2,再由Mn3O4最终转变为α-MnO2.所得MnOx/Ti膜中, α-MnO2晶粒尺寸小于30 nm,结晶度较高,颗粒分布均匀.同时,由于其含有不饱和配位的锰原子和氧空位以及与基体Ti之间存在键合作用,表现出优异的电化学性能和催化性能.以450 ℃焙烧所得的α-MnO2/Ti为阳极构建电催化膜反应器催化氧化苯甲醇.在反应温度为25 ℃, 50mmol·L-1苯甲醇水溶液,电流密度为2 mA·cm-2,停留时间为15 min的条件下,膜反应器苯甲醇转化率达64%,苯甲醛选择性为79%.<br>MnOx nanoparticles obtained by the emulsion method were loaded on a microporous tubular titanium membrane to prepare a functional MnOx/Ti electrocatalytic membrane. The effects of calcination temperature on the crystal structure of MnOx as well as the electrochemical properties and catalytic performance to oxidize benzyl alcohol of MnOx/Ti membrane were systematically investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), cyclic voltammetry (CV), chronoamperometry (CA), and other characterization methods. The results indicated that the crystal structure of MnOx was gradually transformed from Birnessite-MnO2 to K0.27MnO2, and finally to α-MnO2 from Mn3O4 with increasing calcination temperature. The α-MnO2 particles in the MnOx/Ti electrocatalytic membrane showed high crystallinity and uniform particle size (less than 30 nm). The superior electrochemical properties and catalytic performance of α-MnO2/Ti membrane obtained at a calcination temperature of 450 ℃ could be attributed to the binding effects between unsaturated coordination atoms of Mn and oxygen vacancies with the Ti substrate. The α-MnO2/Ti membrane obtained at 450 ℃ was used as the anode to assemble an electrocatalytic membrane reactor to oxidize benzyl alcohol. 64% conversion of benzyl alcohol and 79% selectivity to benzaldehyde was achieved under the operating conditions: reaction temperature 25 ℃, aqueous benzyl alcohol solution of 50 mmol·L-1, current density 2 mA·cm-2, and residence time 15 min
%U http://www.whxb.pku.edu.cn/CN/Y2015/V31/I8/1567