TiO2负载单金属镍(铂)催化剂在甲烷解离反应中抗积碳能力的理论研究  

Theoretical Studies on Suppression of Carbon Deposition over Titania Supported Monometallic Nickel(Platinum) Catalysts in Methane Dissociation

作　　者：王秀军[1] 齐秋红[1] 陈丽[1] 

机构地区：[1]广东省燃料电池技术重点实验室华南理工大学化学与化工学院,广州510640

出　　处：《高等学校化学学报》2014年第10期2138-2145,共8页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:20975040,21173086)、国家自然科学基金(广东基金)重点项目(批准号:U1301245);广东省自然科学基金(批准号:10351064101000000)资助~~

摘　　要：研究碳原子在TiO2(101)负载镍或铂原子上的吸附行为对于阐明积碳问题提供了一个热力学线索.广义梯度近似密度泛函理论的PBE计算结果表明,镍在TiO2表面最稳定构型的吸附能为347.16 kJ/mol,铂对应的最稳定构型的吸附能为315.9 kJ/mol,而且2种金属的最稳定构型均处于TiO2表面2个O2c原子之间的桥位.吸附金属原子后,TiO2的态密度图中各电子峰向低能量方向移动,体系趋于稳定.从态密度图可知,碳的p轨道与金属原子的d轨道发生叠加,说明碳原子与金属原子成键,从而使吸附后Ni或Pt与O原子之间的相互作用减弱.碳原子吸附在Ni/TiO2(101)和Pt/TiO2(101)表面的最佳吸附结构的吸附能分别为474.19和570.08 kJ/mol,说明TiO2负载铂催化剂在甲烷重整反应中抗积碳能力较强.The adsorption behavior of carbon atom adsorbed by one atom ot 1＇~1 or t＇t supponeu oti m~ a,,,＊ TiO2（ 101 ） surface was studied which could provide a thermodynamics clue for elucidating the carbon deposi- tion. The calculated results by PBE based on generalized gradient approximation indicated that the adsorption energy of the most stable configuration for Ni and Pt adsorbed on the TiO2 surface were 347.16 and 315.9 kJ/ mol, respectively, corresponding to the bridge site between the two O2c atoms. After adsorbing metal atom, the density of state for TiO2 moved to the lower energy, leading to a more stable system. The density of state was confirmed that there was a significant overlap between p-orbital of carbon atom and d-levels of the metal atom, indicating the effective bonding of carbon and metal atoms, which could attenuate the interaction between these two atoms. When carbon was adsorbed on the Ni/TiO2（ 101 ） or Pt/TiO2（ 101 ） surface, the adsorption energies for the preferable structure were 474. 19 or 570. 08 kJ/mol. Our work demonstrates the Pt supported on TiO2 support possessed the better ability for inhibiting the carbon deposition.

关 键 词：二氧化钛 积碳 吸附 镍 铂 甲烷解离反应 

分 类 号：O641[理学—物理化学]