γ-Fe_(2)O_(3)表面HCl对汞的吸附和氧化机理研究  

Study on the adsorption and oxidation mechanism of mercury by HCl overγ-Fe_(2)O_(3) catalyst

作　　者：周文波 牛胜利[1] 王俊 李颖 韩奎华[1] 王永征[1] 路春美[1] 朱英 ZHOU Wen-bo;NIU Sheng-li;WANG Jun;LI Ying;HAN Kui-hua;WANG Yong-zheng;LU Chun-mei;ZHU Ying(School of Energy and Power Engineering,Shandong University,Jinan 250061,China;Advanced Materials Institute,Qilu University of Technology(Shandong Academy of Science),Jinan 250014,China)

机构地区：[1]山东大学能源与动力工程学院,山东济南250061 [2]齐鲁工业大学(山东省科学院)新材料研究所,山东济南250014

出　　处：《燃料化学学报》2021年第11期1716-1723,共8页Journal of Fuel Chemistry and Technology

基　　金：山东省重大科技创新工程(2019JZZY020305)资助。

摘　　要：本研究采用密度泛函理论(DFT)研究了在γ-Fe_(2)O_(3)表面HCl对Hg^(0)的吸附和催化氧化的作用机制。构建了Hg^(0)、HCl、HgCl和HgCl_(2)在γ-Fe_(2)O_(3)(001)表面的吸附模型,分析了HCl对γ-Fe_(2)O_(3)表面催化氧化Hg^(0)的作用机理,并通过反应路径的能量分布测定,研究了γ-Fe_(2)O_(3)表面Hg^(0)的氧化过程。结果表明,Hg^(0)倾向于化学吸附在γ-Fe_(2)O_(3)(001)表面Fe_(oct)位。HCl在催化剂表面进行解离吸附,形成吸附态Cl和羟基,从而促进Hg^(0)的吸附。HgCl以分子形式化学吸附在γ-Fe_(2)O_(3)(001)上,并作为Hg^(0)氧化过程的中间体。HgCl_(2)倾向在γ-Fe_(2)O_(3)表面上的平行吸附。同时,HCl在γ-Fe_(2)O_(3)(001)上氧化Hg^(0)遵循L-H机理,即化学吸附的Hg^(0)与解离吸附的HCl反应,且HCl对Hg^(0)的非均相氧化通过两步反应途径进行,即Hg^(0)(ads)→HgCl(ads)→HgCl_(2)(ads)。The mechanism of adsorption and oxidation of Hg^(0) by HCl onγ-Fe_(2)O_(3) surface was investigated by density functional theory(DFT)calculation.The adsorption models of Hg^(0),HCl,HgCl and HgCl_(2) onγ-Fe_(2)O_(3)(001)surface were constructed,and the reaction mechanism of catalytic oxidation of Hg^(0) by HCl onγ-Fe_(2)O_(3) surface was analyzed.The results illustrate that the Hg^(0) tends to be chemically adsorbed at Fe_(oct) site.HCl can be dissociated and adsorbed on the surface of the catalyst to form adsorbed Cl and hydroxyl groups,and promote the adsorption of Hg^(0).HgCl can be molecularly chemisorbed uponγ-Fe_(2)O_(3)(001)and act as an intermediate.HgCl_(2) tends to be adsorbed in parallel on the surface ofγ-Fe_(2)O_(3).HCl oxidizes Hg^(0) onγ-Fe_(2)O_(3)(001)following the L-H mechanism:chemically adsorbed Hg^(0) reacts with dissociatively adsorbed HCl.By measuring the energy distribution of the reaction path,the oxidation process of Hg^(0) on the surface ofγ-Fe_(2)O_(3) was studied.The heterogeneous oxidation of Hg^(0) by HCl proceeds on a two-step reaction pathway:Hg^(0)(ads)→HgCl(ads)→HgCl_(2)(ads).

关 键 词：Hg^(0) γ-Fe_(2)O_(3) HCL 催化氧化机理 DFT 

分 类 号：TQ534[化学工程—煤化学工程]