氮掺杂石墨烯负载单原子Zr催化CO2加氢的密度泛函理论研究

Density Functional Theory Calculation of CO2 Hydrogenation over Single Zr Atom Incorporated N Doped Graphene

中文关键词:  CO₂催化加氢  石墨烯  密度泛函理论  甲酸  CO

英文关键词:CO₂ catalytic hydrogenation  graphene  density functional theory  formic acid  CO

中文摘要:

      基于密度泛函理论计算, 研究了H₂和CO₂在氮掺杂石墨烯负载单原子Zr催化剂(ZrN_x-Gr)上的吸附和CO₂催化加氢反应. H₂和CO₂在ZrN₃-Gr上单独吸附的吸附能分别为-0.49和-2.17 eV, 在H₂和CO₂共吸附状态下, 吸附能为-2.24 eV, 均高于在ZrN₄-Gr表面的吸附能, 表明ZrN₃-Gr表面更利于CO₂加氢反应的发生. 在ZrN₃-Gr表面, CO₂在共吸附后保持了其单独吸附时的特性, 削弱了H₂分子的吸附. CO₂在ZrN_x-Gr表面催化加氢反应起始于H₂和CO₂的共吸附构型, 沿反式HCOOH路径形成甲酸盐(HCOO*)中间体, 然后HCOO*基团吸附H原子形成反式甲酸, 在ZrN₃-Gr和ZrN₄-Gr表面该路径的反应能垒分别为1.85和2.48 eV. 另一路径为产生CO与H₂O的反应, 在ZrN₃-Gr和ZrN₄-Gr表面的反应能垒分别为1.86和1.73 eV, 表明ZrN₃-Gr更利于CO₂加氢生成甲酸反应的发生, 而ZrN₄-Gr表面更利于CO的产生.

英文摘要:

      Based on Density functional theory calculations, the adsorption of H₂ and CO₂ on nitrogen doped Graphene supported monatomic Zr (ZrN_x-Gr) and the catalytic hydrogenation of CO₂ were studied. The adsorption energies of H₂ and CO₂ on ZrN₃-Gr alone are −0.49 and −2.17 eV, respectively. In the co-adsorption state of H₂ and CO₂, the adsorption energy is −2.24 eV, which is higher than the adsorption energy on ZrN₄-Gr surface, indicating that the ZrN₃-Gr surface is more conducive to the occurrence of CO₂ hydrogenation reaction. On the surface of ZrN_x-Gr, CO₂ maintains its individual adsorption characteristics after co-adsorption, weakening the adsorption of H₂ molecules. The catalytic hydrogenation reaction of CO₂ on ZrN₃-Gr surface begins with the co-adsorption configuration of H₂ and CO₂, forming formate (HCOO*) intermediates along the trans HCOOH pathway. Then, the HCOO * group adsorbs H atoms to form trans formic acid. The reaction energy barriers of this pathway on ZrN₃-Gr and ZrN₄-Gr surfaces are 1.85 and 2.48 eV, respectively. Another pathway is the reaction between CO and H₂O, with reaction energy barriers of 1.86 and 1.73 eV on the ZrN₃-Gr and ZrN₄-Gr surfaces, respectively. This indicates that ZrN₃-Gr is more conducive to the reaction of CO₂ hydrogenation to formic acid, while the ZrN₄-Gr surface is more conducive to the production of CO.