Operando Insight into the Oxygen Evolution Kinetics on the Metal-Free Carbon-Based Electrocatalyst in an Acidic Solution
Operando Insight into the Oxygen Evolution Kinetics on the Metal-Free Carbon-Based Electrocatalyst in an Acidic Solution
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Operando 深入了解酸性溶液中无金属碳基电催化剂的析氧动力学
DOI：
10.1021/acsami.9b09315
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发表时间：
2019
影响因子：
9.5
通讯作者：
Qinghua Liu
中科院分区：
文献类型：
--
作者：
Xu Zhao;Hui Su;Weiren Cheng;Hui Zhang;Wei Che;Fumin Tang;Qinghua Liu
Operando对工作条件下催化动力学的深入了解对于进一步合理设计先进的催化剂以实现高效的可再生能源应用非常重要。在这里，我们将一种普遍存在的碳材料作为高效的酸性析氧反应（OER）电催化剂，通过简单可控的“氨基辅助聚合和碳化”策略合成。这种直接负载在碳纸上的无金属富氨基层次网络碳（amino-HNC）框架可以在酸性溶液中以281 mV的过电位和96 mV的Tafel斜率催化OER，并在100 h的析氧操作后保持98%的初始催化活性。利用operando同步红外光谱，在酸性介质中的OER过程中，在氨基- hnc电催化剂上观察到由*O中间体吸附在活性H2N - C = C基团上形成的关键结构演化H2N - (*O - C) C。此外，理论计算表明，氨基自由基对C = C的sp2电子结构的优化可以有效地降低H2N-C = C部分上*O中间体的动力学形成屏障，从而促进了明显的酸性氧参与催化。
Operando insight into the catalytic kinetics under working conditions is important for further rationalizing the design of advanced catalysts toward efficient renewable energy applications. Here, we enable a ubiquitous carbon material as an efficient acidic oxygen evolution reaction (OER) electrocatalyst, synthesized via a facile and controllable “amino-assisted polymerization and carbonization” strategy. This as-developed metal-free amino-rich hierarchical-network carbon (amino-HNC) framework directly supported on carbon paper can catalyze OER at a quite low overpotential of 281 mV and a small Tafel slope of 96 mV dec–1in an acid solution, and maintain ∼98% of its initial catalytic activity after 100 h oxygen evolution operation. By using the operando synchrotron infrared spectroscopy, a crucial structurally evolved H2N–(*O–C)–C, formed by adsorbing the *O intermediate on the active H2N–C═C moiety, is observed on amino-HNC electrocatalysts during the OER process in the acid medium. Furthermore, theoretical calculations reveal that the optimization of the sp2electronic structure of C═C by amino radicals could effectively lower the kinetic formation barrier of the *O intermediate on the H2N–C═C moiety, contributing to a prominent acidic oxygen-involved catalysis.