Ca_(2)Mn_(3)O_(8)纳米微球的合成及催化分解过氧化氢性能的研究

Synthesis of Ca_(2)Mn_(3)O_(8) Nanospheres and Study on Catalytic Decomposition of Hydrogen Peroxide

类芬顿反应是指除Fe(Ⅱ)以外的催化剂对H_(2)O_(2)起到催化作用的一类反应,类芬顿催化体系的固体催化剂具有易于分离和回收、工作pH范围宽、效率高等优点,使其在废水处理中具有广阔的应用前景。Mn基氧化物(Mn_(2)O_(2))具有良好的催化活性,但是其容易发生相变从而导致催化剂严重失活,可通过构建多元金属氧化物来稳定催化剂的相结构和催化活性。采用共沉淀法合成了双金属单斜相锰酸钙氧化物(Ca_(2)Mn_(3)O_(8))纳米微球。结果表明,Ca_(2)Mn_(3)O_(8)具有优异的催化分解H_(2)O_(2)性能,在15分钟内对H_(2)O_(2)(100 mL,1000 ppm)的降解率达100%,5次循环后,Ca_(2)Mn_(3)O_(8)纳米微球仍然具有良好的可重复性和高稳定性。Ca的引入极大地改善了Ca_(2)Mn_(3)O_(8)的结构稳定性,Ca、Mn双位点协同作用共同提升了催化分解H_(2)O_(2)的性能。

Fenton-like reactions are those in which H_(2)O_(2)is catalyzed by catalysts other than Fe(Ⅱ).Fenton-like catalytic system has broad application prospects in wastewater treatment due to the advantages of solid catalyst easy separation and recovery,wide operating pH range and high efficiency.Mn-based oxide(Mn_(2)O_(2))exhibits good catalytic activity,but it is prone to phase transformation and leads to serious deactivation of the catalyst.The construction of multi-metal oxides is beneficial to stabilize the catalyst phase structure and catalytic activity.In this work,bimetallic monoclinic calcium manganate(Ca_(2)Mn_(3)O_(8))oxide nanospheres were synthesized by coprecipitate method.The experimental results showed that Ca_(2)Mn_(3)O_(8)showed excellent catalytic decomposition of H_(2)O_(2),and the degradation rate of H_(2)O_(2)(100 mL,1000 ppm)was 100%within 15 minutes.After 5 cycles,Ca_(2)Mn_(3)O_(8)nanospheres still showed good repeatability and high stability.The introduction of Ca improves the structural stability of Ca_(2)Mn_(3)O_(8),and the synergistic effect of Ca and Mn sites improves the catalytic decomposition performance of H_(2)O_(2).