A density functional theory study of CO2 hydrogenation to methanol over Pd/TiO2 catalyst: The role of interfacial site
A density functional theory study of CO2 hydrogenation to methanol over Pd/TiO2 catalyst: The role of interfacial site
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DOI：
10.1016/j.ijhydene.2019.12.099
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发表时间：
2020-02
影响因子：
7.2
通讯作者：
Zhiliang Ou;J. Ran;Juntian Niu;Changlei Qin;Wei He;Lin Yang
中科院分区：
文献类型：
--
作者：
Zhiliang Ou;J. Ran;Juntian Niu;Changlei Qin;Wei He;Lin Yang
金属与载体之间的界面对co2加氢制甲醇的活性和选择性有非常显著的影响，但对其在反应过程中的作用还缺乏深入的研究。本研究基于周期密度泛函理论计算，对模型Pd/ tio2催化剂上co2加氢合成甲醇进行了研究，考察了可能的路线，揭示了反应机理和活性位点。电荷密度差和Millikan电荷分析表明，吸附在界面位置的co2由于从催化剂上获得电荷而被活化，并转化为化学吸附的CO2δ−。发现界面是co2后续加氢过程的活性位点，而金属钯为H2的解离提供了活性位点。此外，还存在金属-载体相互作用，Pd颗粒处形成的H与溢出吸附在界面处的co2和中间体发生反应，在载体表面生成甲醇。此外，RWGS + CO- hydro路线被确定为甲醇合成的主要途径，CO加氢成HCO是速率决定步骤。
The interface between metal and support has a very significant influence on the activity and selectivity of the CO2hydrogenation to methanol, but there is still lack of investigation in understanding its role in the reaction process. In the current work, the synthesis of methanol through CO2hydrogenation on a model Pd/TiO2catalyst was studied based on the periodic density functional theory calculation, and the reaction mechanism and active sites were revealed after examining the possible routes. The charge density difference and Millikan charge analysis demonstrate that CO2adsorbed at the interfacial site is activated due to obtaining charge from the catalyst, and it is transformed into chemisorbed CO2δ−. It is found that interface is the active site for the subsequent hydrogenation process of CO2while metal Pd provides an active site to the dissociation of H2. Moreover, there is a metal-support interaction, where the formed H at the Pd particles reacts with the CO2and intermediates adsorbed at interface by the spillover, and the methanol is produced on the support surface. In addition, the RWGS + CO-Hydro route is determined to be the dominant pathway for methanol synthesis, and CO hydrogenation to HCO is the rate-determining step.