As_(2)O_(3)与Cu-ZSM-5催化剂的相互作用机理  

Adsorption mechanism of As_(2)O_(3) and Cu-ZSM-5catalysts

作　　者：张欢 史一林 刘梁 王晨星 孙瑞彬 贾里 金燕[1] ZHANG Huan;SHI Yi-lin;LIU Liang;WANG Chen-xing;SUN Rui-bin;JIA Li;JIN Yan(College of Electrical and Power Engineering,Taiyuan University of Technology,Taiyuan 030024,China;School of Mechanical Engineering,Tianjin University,Tianjin 300354,China)

机构地区：[1]太原理工大学电气与动力工程学院,山西太原030024 [2]天津大学机械工程学院,天津300354

出　　处：《中国环境科学》2024年第4期2003-2010,共8页China Environmental Science

基　　金：国家自然科学基金资助项目(U1910214)。

摘　　要：基于密度泛函理论计算了NO和As_(2)O_(3)在Cu-ZSM-5表面的吸附性能.通过确立As_(2)O_(3)在Cu-ZSM-5表面的最佳吸附位点,对As3+在其活性位点吸附的反应路径进行研究,计算As在催化剂上的吸附反应活化能垒和决速步骤,揭示As_(2)O_(3)与活性位点Cu-O-Cu的成键机制和相互作用机理.结果表明,NO和As_(2)O_(3)都以非氧端吸附在Cu-ZSM-5活性位点Cu-O-Cu的晶格氧位,吸附能分别为-218.515kJ/mol和-206.422kJ/mol,吸附过程中有电荷转移且发生了强烈的相互作用.As_(2)O_(3)在Cu-ZSM-5活性位点Cu-O-Cu的晶格氧上的氧化过程分两步进行,As^(3+)作为Lewis碱与Lewis酸中心的Cu-O-Cu发生非均相氧化反应,第一阶段的氧化产物As_(2)O_(4)在相邻的活性位点上发生二次氧化反应,生成的As_(2)O_(5)成为As^(3+)吸附后的主要存在形式.其中,生成As_(2)O_(4)的反应阶段需要跨越242.75kJ/mol的能垒,成为整个氧化进程的决速步骤.The adsorption properties of NO and As_(2)O_(3) over Cu-ZSM-5surface were calculated based on density functional theory in this paper.By determining the optimum adsorption site of As_(2)O_(3) over Cu-ZSM-5,the reaction pathway of As3+adsorbed on its active site was investigated,and the activation energy barriers and decisive speed steps of As adsorption reaction on the catalyst were calculated,to reveal the bonding and interaction mechanisms of the reaction between As_(2)O_(3) and Cu-O-Cu.The results show that the non-oxygen sites of NO and As_(2)O_(3) are adsorbed on the lattice oxygen sites of active site Cu-O-Cu and the adsorption energies are-218.515kJ/mol and-206.422kJ/mol,respectively.The loss of charge suggests that they interact strongly during adsorption process.The oxidation of As_(2)O_(3) on lattice oxygen of Cu-O-Cu is divided into two steps.As^(3+),as Lewis base,is easy to react with Cu-O-Cu as Lewis acid center,and the oxidation product of the first stage,As_(2)O_(4),undergoes a secondary oxidation reaction at the adjacent active site.As_(2)O_(5) becomes the main form after As^(3+)adsorption.The reaction pathway to produce As_(2)O_(4) has to overcome energy barrier of 242.75kJ/mol,which becomes the decisive speed step of the whole oxidation process.

关 键 词：CU-ZSM-5 As_(2)O_(3) 吸附 氧化反应 能垒 

分 类 号：X511[环境科学与工程—环境工程]