第一性原理研究O_2在CrN_4掺杂石墨烯上的氢化

掺杂是调制graphene催化特性的有效方法 .掺杂的石墨烯,因其具有对氧还原反应具有较高的活性,而作为一种新型高效质子交换膜燃料电池阴极材料.采用包含色散力校正的第一性原理的密度泛函理论方法 (DFT-D)系统的研究了O_2在CrN_4掺杂的石墨烯上的吸附和氢化特性.结果表明:(1)O_2倾向于以side-on模式吸附在Cr顶位,形成O-Cr-O三元环结构,吸附能为1.75 e V;(2)O_2在Cr N4-Gra上更倾向于直接分解成O+O,并进一步氢化为O+OH,反应的限速步为O_2的分解,相应的反应势垒为0.48 e V.

First-principles study on the hydrogenation of the O2 on CrN4 embedded Graphene

Doping is a useful method to modulate the catalytic properties of graphene. Doped graphene, for its high oxygen reduction reaction activity, is a new and efficient cathode material of proton exchange membrane fuel cell. The O2 adsorption and hydrogenation properties on the CrN4 doped graphene are investigated from the dispersion-corrected density functional theory (DFT-D) method. It is found that: (1) O2 prefers to stay on the top of the Cr with the side-on configuration, forming the O-Cr-O three member ring; (2) the direct decomposition of O2 into O + O on the CrN4-Gra is preferable, and the atomic O is subsequently hydrogenated into O + OH. The corresponding reaction rate-limiting step is the decomposition of the O2 with the reaction barrier of 0.48 eV.