H.Adelkhani
,
M.Ghaemi
,
S.M.Jafari
材料科学技术（英）
Pulse current technique was applied for the preparation of novel electroactive manganese dioxide and possible influences of different electrokinetic phenomena on material characteristics were discussed. The characterizations of pulse deposited sample (pcMD) were carried out by different techniques: Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method, Raman spectroscopy, and atomic force microscopy (AFM). SEM image revealed that pulse current could improve the current distribution. This was confirmed by AFM images showing a decrease in surface roughness of pcMDs in comparison to amorphous samples, which were deposited by direct current (dcMD). Higher distortion of MnO6 octahedral environment of dcMD was detected by FTIR and Raman spectroscopy. Cyclic voltammetric (CV) measurements showed a generally higher energy level drained from the second electron discharge of pcMD. This is mainly attributed to a higher surface area and a lower diffusion pass of electrons and protons arisen via a rather unique nanostructural arrangement of pcMD grains. Results indicate a higher surface area available for the non homogenous second electron discharge of pcMD grains.
关键词:
Manganese dioxide
,
null
,
null
,
null
樊铖
,
张强
,
魏飞
催化学报
doi:10.1016/S1872-2067(14)60236-9
采用MnO2纳米催化剂促进稠油重组分的低温氧化裂解及高温氧化生热，进而促进火烧油层技术在超稠油油藏开发中的应用，提高火烧油层技术的采收率.结果表明， MnO2促进了稠油的低温裂解，高温生热量并不随燃料沉积量的减少而降低. MnO2的加入促进了低温下小分子的生成，并使高温氧化反应更加温和，提高了高温产物的氧化度.相比无催化剂的氧化反应， MnO2使稠油的低温氧化和高温氧化的表观活化能分别降低了10–30 kJ/mol和20–40 kJ/mol.
关键词:
二氧化锰
,
火烧油层
,
氧化裂解
,
燃料沉积
姜枫
,
朱晓文
,
符宝嵩
,
黄金金
,
肖国民
催化学报
doi:10.1016/S1872-2067(12)60633-0
采用氧化还原法制备了α,δ,γ-MnO2载体,采用原位还原法制备了Au负载量为0.5％-3.0％的Au/γ-MnO2催化剂,并采用X射线衍射、扫描电镜、透射电镜和N2物理吸附等手段对其进行了表征.透射电镜照片表明Au/γ-MnO2催化剂中Au颗粒的大小约为10nm.采用无溶剂存在下的甲苯氧化反应测试所制备样品的催化活性.结果表明,甲苯转化率随着Au负载量的增加而增大.这是由于Au颗粒数量增多,尺寸减小的缘故.同时,负载Au颗粒对苯甲醛具有较高的选择性.Au/γ-MnO2催化剂具有良好的重复使用性.
关键词:
二氧化锰
,
纳米金催化剂
,
甲苯氧化
,
无溶剂
