Liu Yanju, Han Yongzhen, Zhang Zongyao, Zhang Wei, Lai Wenzhen, Wang Yong, Cao Rui
Department of Chemistry , Renmin University of China , Beijing 100872 , China . Email:
Key Laboratory of Applied Surface and Colloid Chemistry , Ministry of Education , School of Chemistry and Chemical Engineering , Shaanxi Normal University , Xi'an 710119 , China.
Chem Sci. 2019 Jan 7;10(9):2613-2622. doi: 10.1039/c8sc04529a. eCollection 2019 Mar 7.
Low overpotential water oxidation under mild conditions is required for new energy conversion technologies with potential application prospects. Extensive studies on molecular catalysis have been performed to gain fundamental knowledge for the rational designing of cheap, efficient and robust catalysts. We herein report a water-soluble Cu complex of tetrakis(4--methylpyridyl)porphyrin (), which catalyzes the oxygen evolution reaction (OER) in neutral aqueous solutions with small overpotentials: the onset potential of the catalytic water oxidation wave measured at current density = 0.10 mA cm is 1.13 V a normal hydrogen electrode (NHE), which corresponds to an onset overpotential of 310 mV. Constant potential electrolysis of at neutral pH and at 1.30 V NHE displayed a substantial and stable current for O evolution with a faradaic efficiency of >93%. More importantly, in addition to the 4e water oxidation to O at neutral pH, can catalyze the 2e water oxidation to HO in acidic solutions. The produced HO is detected by rotating ring-disk electrode measurements and by the sodium iodide method after bulk electrolysis at pH 3.0. This work presents an efficient and robust Cu-based catalyst for water oxidation in both neutral and acidic solutions. The observation of HO during water oxidation catalysis is rare and will provide new insights into the water oxidation mechanism.
对于具有潜在应用前景的新能源转换技术而言，需要在温和条件下实现低过电位水氧化。为了获得有关合理设计廉价、高效且稳健催化剂的基础知识，已对分子催化进行了广泛研究。我们在此报告一种四（4 - 甲基吡啶基）卟啉的水溶性铜配合物（），它在中性水溶液中以小过电位催化析氧反应（OER）：在电流密度 = 0.10 mA cm 下测得的催化水氧化波的起始电位为1.13 V 对标准氢电极（NHE），这对应于310 mV的起始过电位。在中性pH值和1.30 V 对NHE条件下对 进行恒电位电解，显示出用于析氧的稳定可观电流，法拉第效率>93%。更重要的是，除了在中性pH值下将水进行4e氧化生成O 外， 在酸性溶液中还能催化水进行2e氧化生成HO 。通过旋转环盘电极测量以及在pH 3.0下进行大量电解后用碘化钠法检测到生成的HO 。这项工作展示了一种在中性和酸性溶液中用于水氧化的高效且稳健的铜基催化剂。在水氧化催化过程中观察到HO 是罕见的，这将为水氧化机制提供新的见解。
