Verma Manju, Deshpande Parag A
Quantum and Molecular Engineering Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India.
Phys Chem Chem Phys. 2017 Mar 29;19(13):8757-8767. doi: 10.1039/c7cp00556c.
Electronic structural analyses of hydrogen terminated metal doped carbon nanotube/graphene (M-CNT/Gr, MN-CNT/Gr, M = Ru/Rh) and ruthenium cluster decorated carbon nanotube/graphene (Ru-CNT/Gr) were carried out for examining the biomimetic catalytic activity towards CO hydration reaction. The carbonic anhydrase action was followed for the reaction of CO with HO resulting in a bicarbonate ion and a proton. All the catalysts were found to be active for CO hydration and the mechanism proved them to be biomimetic. Interconversion of CO to a HCO ion took place with five elementary steps viz. OH formation by HO dissociation, linear CO complexation, CO bending by nucleophilic attack of an OH ion over CO, HCO ion formation by intramolecular proton migration and HCO ion displacement by HO addition. Free energy landscapes over the catalysts were developed for CO hydration reaction. The activation energies of HO dissociation and CO bending were observed to be substantially smaller over Ru-CNT when compared to those over the other catalysts. Ru-CNT was found to be the best catalyst for CO hydration with the rate limiting step being HCO ion formation.
对氢封端的金属掺杂碳纳米管/石墨烯（M-CNT/Gr，MN-CNT/Gr，M = Ru/Rh）以及钌簇修饰的碳纳米管/石墨烯（Ru-CNT/Gr）进行了电子结构分析，以研究其对CO水合反应的仿生催化活性。跟踪碳酸酐酶的作用，即CO与HO反应生成碳酸氢根离子和质子。发现所有催化剂对CO水合均具有活性，并且该机理证明它们具有仿生特性。CO向HCO离子的相互转化通过五个基本步骤进行，即HO解离形成OH、线性CO络合、OH离子对CO进行亲核攻击使CO弯曲、分子内质子迁移形成HCO离子以及通过HO加成取代HCO离子。针对CO水合反应绘制了催化剂上的自由能分布图。与其他催化剂相比，观察到Ru-CNT上HO解离和CO弯曲的活化能要小得多。发现Ru-CNT是CO水合的最佳催化剂，限速步骤是HCO离子的形成。
