Wang Jiong, Gan Liyong, Zhang Wenyu, Peng Yuecheng, Yu Hong, Yan Qingyu, Xia Xinghua, Wang Xin
School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459, Singapore.
School of Material Science and Engineering, Key Laboratory of Advanced Energy Storage Materials of Guangdong Province, South China University of Technology, Guangzhou 510641, China.
Sci Adv. 2018 Mar 9;4(3):eaap7970. doi: 10.1126/sciadv.aap7970. eCollection 2018 Mar.
Molecularly well-defined Ni sites at heterogeneous interfaces were derived from the incorporation of Ni ions into heteroatom-doped graphene. The molecular Ni sites on graphene were redox-active. However, they showed poor activity toward oxygen evolution reaction (OER) in KOH aqueous solution. We demonstrated for the first time that the presence of Fe ions in the solution could bond at the vicinity of the Ni sites with a distance of 2.7 Å, generating molecularly sized and heterogeneous Ni-Fe sites anchored on doped graphene. These Ni-Fe sites exhibited markedly improved OER activity. The Pourbaix diagram confirmed the formation of the Ni-Fe sites and revealed that the Ni-Fe sites adsorbed HO ions with a bridge geometry, which facilitated the OER electrocatalysis.
通过将镍离子掺入杂原子掺杂的石墨烯中，在异质界面处获得了分子结构明确的镍位点。石墨烯上的分子镍位点具有氧化还原活性。然而，它们在氢氧化钾水溶液中对析氧反应（OER）表现出较差的活性。我们首次证明，溶液中存在的铁离子可以在距离镍位点约2.7 Å的附近键合，生成锚定在掺杂石墨烯上的分子尺寸且异质的镍铁位点。这些镍铁位点表现出显著提高的析氧反应活性。Pourbaix图证实了镍铁位点的形成，并表明镍铁位点以桥式几何结构吸附氢氧根离子，这促进了析氧反应的电催化作用。
