Au10催化CO氧化反应机理的密度泛函理论研究

发布时间：2018-10-24 15:53

【摘要】：采用密度泛函理论方法研究了Au10团簇催化CO氧化反应的详细机理。对CO、O_2、O、CO_24种主要吸附物及CO+O_2、CO_2+O、CO+O和CO+O+O4种共吸附物的吸附行为进行计算,得到最佳活性吸附位。模拟反应分别按照Langmuir-Hinshelwood(LH)机理和Eley-Rideal(ER)机理进行,其中LH机理包括L1、L2两条路径,ER机理包括E1、E2两条路径。通过比较各路径活化能得到:CO+O_2→CO_2+O反应按照LH机理进行的可能性较大,并且相比较L1、L2两条路径,由于反应按照L1路径进行时只需克服33.9和56.4kJ·mol-1的能垒,所以反应更易按照L1路径进行,最佳反应路径为O_2(gas)+CO(gas)→O_2(ads)+CO(gas)→O_2(ads)+CO(ads)→OCOO(ads)→O(ads)+CO_2(ads);CO+O→CO_2反应分别克服6.9和4.3kJ·mol-1能垒,放热352.1kJ·mol-1,说明低温下吸附态的O原子很容易与CO反应生成第2个CO_2分子。
[Abstract]:The detailed mechanism of CO oxidation catalyzed by Au10 clusters was studied by density functional theory (DFT). The adsorption behavior of the main adsorbents of CO,O_2,O,CO_24 and CO _ O _ 2CO _ 2O _ 2O _ O and CO O _ 4 were calculated and the optimum active adsorption sites were obtained. The simulated reactions were carried out according to the Langmuir-Hinshelwood (LH) mechanism and the Eley-Rideal (ER) mechanism, respectively. The LH mechanism includes two paths: L1 and L2, and the ER mechanism includes E1 and E2 pathways. By comparing the activation energies of different paths, it is found that the CO O _ 2 / CO_2 _ O reaction is more likely to be carried out according to the LH mechanism, and compared with the L _ (1) O _ (2) and L _ (2) paths, the energy barriers of 33.9 and 56.4kJ mol-1 only need to be overcome when the reaction is carried out according to the L1 path. So the reaction is easier to follow the L1 path, and the best reaction path is O _ 2 (gas) CO (gas) / O _ S _ 2 (ads) CO (ads) / OCOO (ads) / O (ads) CO_2 (ads); CO O / CO_2 reaction to overcome 6.9 and 4.3kJ mol-1 energy barriers, respectively. The exothermic 352.1kJ mol-1, indicates that the adsorbed O atom can easily react with CO to form a second CO_2 molecule at low temperature.
【作者单位】：浙江海洋学院;浙江工业大学先进催化材料实验室;
【分类号】：O641.1

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