Chemical Dopants on Edge of Holey Graphene Accelerate Electrochemical Hydrogen Evolution Reaction
Chemical Dopants on Edge of Holey Graphene Accelerate Electrochemical Hydrogen Evolution Reaction
复制标题
DOI：
10.1002/advs.201900119
复制
发表时间：
2019-05-17
期刊：
影响因子：
15.1
通讯作者：
Ito, Yoshikazu
中科院分区：
文献类型：
--
作者：
Kumatani, Akichika;Miura, Chiho;Ito, Yoshikazu
用于析氢反应(HER)的碳基无金属催化剂对于可持续氢社会的发展至关重要。多相催化中活性中心的确定是合理设计低成本、高效率催化剂的关键。在这里，通过化学掺杂制备多孔石墨烯，通过原子表征的元素映射、扫描电化学细胞显微镜(SECCM)和密度泛函理论(DFT)计算，揭示了化学掺杂加速HER的原子水平机理。研究发现，石墨烯的边缘结构和氮磷共掺杂两个重要因素的协同作用提高了其活性。扫描电子显微镜证明，含有化学掺杂的石墨烯边缘在电化学上非常活跃。实际上，密度泛函计算表明，吡啶氮原子可能是催化活性中心。由于磷掺杂促进了催化活性氮原子上的电荷积累，因此提高了HER的活性。这些发现为在石墨烯催化剂中设计石墨烯的边缘结构铺平了道路。
Carbon-based metal-free catalysts for the hydrogen evolution reaction (HER) are essential for the development of a sustainable hydrogen society. Identification of the active sites in heterogeneous catalysis is key for the rational design of low-cost and eff icient catalysts. Here, by fabricating holey graphene with chemically dopants, the atomic-level mechanism for accelerating HER by chemical dopants is unveiled, through elemental mapping with atomistic characterizations, scanning electrochemical cell microscopy (SECCM), and density functional theory (DFT) calculations. It is found that the synergetic effects of two important factors-edge structure of graphene and nitrogen/phosphorous codoping-enhance HER activity. SECCM evidences that graphene edges with chemical dopants are electrochemically very active. Indeed, DFT calculation suggests that the pyridinic nitrogen atom could be the catalytically active sites. The HER activity is enhanced due to phosphorus dopants, because phosphorus dopants promote the charge accumulations on the catalytically active nitrogen atoms. These findings pave a path for engineering the edge structure of graphene in graphene-based catalysts.