介孔二氧化锰制备及其催化臭氧氧化草酸研究

Preparation of mesoporous MnO_2 for catalytic ozonation of oxalic acid

采用纳米刻蚀法制备了介孔二氧化锰臭氧催化剂,并考察了其催化臭氧氧化降解草酸的性能.该催化剂高比表面积(142m^2·g^(-1))的有序纳米棒有利于催化剂活性位点的暴露和物质的吸附,从而增强了催化剂的催化活性.羟基自由基是催化臭氧氧化过程中产生的主要活性氧物种,该催化剂的羟基自由基产率是非介孔二氧化锰的2倍;朗缪尔吸附模型表明该催化剂对草酸的吸附能力是非介孔二氧化锰的9.42倍;该催化剂催化降解草酸的准一级反应动力学常数是非介孔二氧化锰的3倍.

A mesoporous MnO2 is prepared by the nanocasting method, and its performance as a catalyst for catalytic ozonation of oxalic acid is investigated. The ordered nanorods with high surface area （142 m2 g-1 ） benefit the active sites exposition and the mass adsorption, thus enhance theefficiency of catalytic ozonation. In the catalytic ozonation, hydroxyl radical is identified as the mainreactive oxygen species,and the productive rate of hydroxyl radical by the mesopo2 times as high as that by the non-mesoporous MnO2. The adsorption capacity of oxalic acid by themesoporous MnO2 is 9. 42 times as high as that by the non-mesoporous MnO2 calculated by theLangmuir adsorption model. The pseudo first-order reaction kinetics constant of the catalyticozonation of oxalic acid by the mesoporous MnO2 is 3 times as much as that by the non-mesoporous MnO2.