H2O2穩(wěn)定性的密度泛函研究

程 學(xué) 禮

(泰山學(xué)院 化學(xué)化工學(xué)院，山東 泰安 271000)

1 前言

雙氧水(H2O2)是一種清潔氧化劑而被廣泛用于造紙和化學(xué)合成[1]，能夠參與多種氧化還原反應(yīng)[2-4].H2O2還常被用于有機(jī)污染物的降解[5-7]，著名的芬頓反應(yīng)就是用H2O2和Fe2+的混合溶液氧化有機(jī)化合物，特別是難降解有機(jī)污染物[8-9].

H2O2可以通過氫氣和氧氣直接反應(yīng)或氧氣電還原等方法低成本合成[10-11].然而，無論在氣相還是溶液中H2O2均不穩(wěn)定，易分解釋放氧氣(ΔH=-98.23 kJ/mol)；H2O2對光照敏感，雙氧水在λ= 275-366nm下均可分解[12-13].在金屬陽離子、碘離子和金屬氧化物催化下，H2O2能夠快速分解[14-17].一般情況下，H2O2分解為2個羥基自由基參與反應(yīng)，因此，O-O鍵長的變化在H2O2分解過程中將扮演重要角色.

2 計(jì)算方法

3 結(jié)果與討論

3.1 基態(tài)結(jié)構(gòu)

圖1 B3LYP和M06-2X方法結(jié)合得到的分子結(jié)構(gòu)(鍵長的單位是nm，括號內(nèi)為氣相鍵長)

3.2 發(fā)射光譜

表1 TD-M062X模擬得到的4種結(jié)構(gòu)發(fā)射光譜的最大發(fā)射波長λmax(振子強(qiáng)度f)和躍遷軌道(躍遷貢獻(xiàn)比). λmax以nm為單位.方括號內(nèi)數(shù)據(jù)為氣相數(shù)據(jù)

3.3 激發(fā)態(tài)結(jié)構(gòu)

圖2 T1態(tài)優(yōu)化結(jié)構(gòu)參數(shù)

4 結(jié)論

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