空氣中對人體有害的物質例如: volatile organic compounds (VOCs)、氮氧化物(NOx)、一氧化碳(CO)、粉塵微粒(PM10)…等。2009年，國際癌症研究機構（IARC）認為甲醛會引起鼻咽癌和白血病，如何去除甲醛，是十分迫切並且有意義的議題。許多物理及化學方法被應用於去除空氣中的甲醛，常見的方法有活性碳吸附(AC),光催化劑氧化 (PCO)以及催化劑氧化.
在這篇論文中，使用密度泛函理論(DFT) 模擬不同過渡金屬(釩，鈷，鎳) 吸附在含硼石墨烯上的穩定催化劑結構，再進行甲醛在此催化劑上乾淨或含氧表面吸附、分解或轉換成CH4 或CH3OH 等分子的計算。
甲醛吸附在V4, Co4, Ni4表面上，最穩定結構的吸附能分別為-3.51,-2.29,-1.82 eV，首先我使用態密度(Density of states) 以及電荷密度差分析，探討甲醛吸附前後電子性質的變化。接著進行甲醛在表面上斷C-H 、C-O 鍵的計算，發現甲醛分解的主要路徑是經由連續脫氫後生成CO，再將CO氧化成CO2 脫附。另外，我亦模擬甲醛轉換成甲醇與甲烷的反應。在V4 和Ni4表面C-O鍵仍然是可能斷裂並且產生CH2 吸附在表面上，接著在Ni4表面有利於CH2被氫化生成CH4 。而甲醇生成則是在含氧的表面下氫化甲醛有較低的能障。

Nowadays controlling indoor air quality is attracting immense research attention since humans are spending more time in the indoor activities. Formaldehyde (HCHO) is the most common highly toxic volatile carcinogen, which is found in many households and offices. The International Agency for Research on Cancer (IARC) concluded in 2009 that longtime exposure to HCHO causes nasal tumors, nasopharyngeal cancer and leukaemia. Etc. In order to clean the indoor air, many strategies have been proposed to remove HCHO. However, catalytic oxidative decomposition of HCHO is considered the most promising approach for removal of indoor HCHO, because of its environmental friendliness.
In this work, with the aid of density functional (DFT) calculations, I have investigated the possible decomposition pathways of HCHO on the metal clusters (V, Co, Ni) supported boron-doped graphene surface. Also, I considered the presence of oxygen on the above decomposition reactions. The results show that, the dehydrogenation reactions of HCHO on the metal clusters are possible and possesses lower energy barrier. However, the energy for the desorption of CO and CO2 are found to be significantly large. Moreover, the formation of CH4 or CH3OH as side reactions at room temperature indicates yet another potential application of the designed systems.

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