熔盐辅助微波法制备g-C_3N_4包覆MgO-Al_2O_3-Fe_2O_3异质结催化剂及其光催化制过氧化氢性能（英文）  

Photocatalytic Production of Hydrogen Peroxide Using g-C_3N_4 Coated MgO-Al_2O_3-Fe_2O_3 Heterojunction Catalysts Prepared by a Novel Molten Salt-Assisted Microwave Process

作　　者：陈鑫[1] 胡绍争[1] 李萍[1] 李薇[1] 马宏飞[1] 陆光[1] 

机构地区：[1]辽宁石油化工大学化学化工与环境学部,辽宁抚顺113001

出　　处：《物理化学学报》2017年第12期2532-2541,共10页Acta Physico-Chimica Sinica

基　　金：supported by the National Natural Science Foundation of China(41571464);Education Department of Liaoning Province,China(L2014145);Natural Science Foundation of Liaoning Province,China(201602467)~~

摘　　要：工业上,双氧水的生产采用的是蒽醌法。此方法采用多步加氢和氧化过程,因此能耗很大。光催化制过氧化氢技术作为可持续和环境友好的新工艺,是传统蒽醌和电化学法的优秀替代者。本文采用熔盐辅助微波法制备了g-C_3N_4包覆MgO-Al_2O_3-Fe_2O_3异质结催化剂。制备的异质结催化剂在可见光下表现出优异的光催化制过氧化氢性能。熔盐的引入改变催化剂形貌的同时也影响了原料三聚氰胺的缩聚度,进而影响了其能带结构。制备的包覆结构能使两组分形成最大面积的异质结和强相互作用。这种强相互作用有利于光生电子-空穴对的分离和界面迁移,进而提高了过氧化氢的生成速率。制备的异质结催化剂的双氧水平衡浓度和生成速率分别为6.3 mmol·L^(-1)和1.42 mmol·L^(-1)·h^(-1),远高于两个单组份。不仅如此,制备的异质结催化剂还能抑制过氧化氢的分解。本文通过自由基捕获实验探讨了可能的反应机理和电子转移路径。H202 is industrially produced by the anthraquinone method, in which energy consumption is high because it involves multistep hydrogenation and oxidation reactions. Photocatalytic production of H202 has received increasing attention as a sustainable and eco-friendly alternative to conventional anthraquinone-based and electrochemical production processes. Herein, we report a novel molten salt-assisted microwave process for the synthesis of a g-C3N4-coated MgO-AI203-Fe203 （MAFO） heterojunction photocatalyst with outstanding H202 production ability. The addition of a molten salt during synthesis changes the morphology of the as-prepared catalysts and influences the degree of polycondensation of melamine, leading to a change in the band gap energy. The cladding structure forms the maximum area of the heterojunction, leading to strong electronic coupling between the two components. This strong electronic coupling results in a more effective separation of the photogeneratedelectron-hole pairs and a faster interfacial charge transfer, leading to higher H202 formation rate. The equilibrium concentration and formation rate of H202 over the as-prepared heterojunction catalyst were 6.3 mmoI-L-1 and 1.42 mmoI.L-l.h-~, which are much higher than that reported for g-C3N4 and MAFO individually. In addition, the H202 decomposition rate also decreases over the as-prepared heterojunction catalysts. A possible mechanism and the electron transfer routes have been proposed based on a free radical trapping experiment.

关 键 词：石墨相氮化碳 包覆结构 异质结 制过氧化氢 熔盐辅助微波法 

分 类 号：O643.36[理学—物理化学] O644.1[理学—化学] TQ123.6[化学工程—无机化工]