The mechanism of oxygen reduction reaction on CoN4 embedded graphene: A combined kinetic and atomistic thermodynamic study
The mechanism of oxygen reduction reaction on CoN4 embedded graphene: A combined kinetic and atomistic thermodynamic study
复制标题
CoN4 嵌入石墨烯上的氧还原反应机理：动力学和原子热力学相结合的研究
DOI：
10.1016/j.ijhydene.2016.08.011
复制
发表时间：
2016
影响因子：
7.2
通讯作者：
Yang Zongxian
中科院分区：
文献类型：
--
作者：
Zhang Xilin;Lu Zhansheng;Yang Zongxian
采用第一性原理方法计算了CoN 4嵌入石墨烯（CoN 4-gra）上氧还原反应（ORR）可能的基元反应步骤的动力学活化能垒和热力学自由能变化.结果表明，CoN 4-gra能促进ORR沿着沿着4 e −途径进行，并通过连续的加氢反应最终生成两个H2O. OOH还原为O和H2O的最大势垒为0.69 eV，被认为是动力学速率决定步骤（RDS）。热力学计算结果表明，当电极电位低于0.58 V时，4 e −途径的ORR沿着基本台阶呈下降趋势。最后一步，OH还原为H2O，具有最大的ΔG值（−0.58 eV），作为4 e −途径的热力学RDS。HOOH生成/解离的大/小能垒和小/大热力学驱动力也表明，2 e −途径对CoN 4-gra的ORR不如4 e −途径有利。
The kinetic activation barriers and the thermodynamic free energy changes for the probable elementary reaction steps of oxygen reduction reaction (ORR) are calculated by the first principles methods to clarify the debate whether the 2e−or 4e−pathway dominates the ORR on the CoN4embedded graphene (CoN4-gra). It is found that the CoN4-gra can promote the ORR to proceed along a 4e−pathway and to finally generate two H2O by successive hydrogenation reactions. The reduction of OOH into O and H2O with the largest barrier of 0.69 eV is suggested to be the kinetic rate-determining step (RDS). The thermodynamics results show that the elementary steps of ORR along the 4e−pathway are downhill at the electrode potential lower than 0.58 V. The last step, the reduction of OH into H2O with the largest ΔG value (−0.58 eV), functions as the thermodynamic RDS of the 4e−pathway. The large/small energy barriers and small/large thermodynamic driving forces for the generation/dissociation of HOOH indicate also that the 2e−pathway is less favorable than the 4e−pathway for ORR on CoN4-gra.