Qiu Chunyu, Cai Fuxian, Wang Yuan, Liu Yijun, Wang Qingxiang, Zhao Chuan
College of Chemistry and Environment, Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000, PR China.
School of Chemistry, The University of New South Wales, Sydney 2052, Australia.
J Colloid Interface Sci. 2020 Apr 1;565:351-359. doi: 10.1016/j.jcis.2019.12.070. Epub 2019 Dec 17.
It is a highly desired yet challenging task to replace rare and expensive noble metal catalysts with inexpensive and earth-abundant metal ones in electrochemical sustainable chemistry field. Herein, the bimetallic zinc-cobalt layered double hydroxide nanosheets (ZnCo-LDH NS) have been facilely synthesized using 2-methylimidazole as a bifunctional alkali source (OH) and a morphological controlling reagent by the one-step room-temperature reaction. The mechanism study shows that the weak organic base of 2-methylimidazole-induced slow release of OH in water/ethanol is the controlling factor for the formation of the LDH nanosheets. The ZnCo-LDH NS modified on glassy carbon electrode exhibited an overpotential of 385 mV at 10 mA cm and a Tafel slope of 108 mV dec in 1.0 M KOH for oxygen evolution reaction, outperforming the corresponding the monometal oxides of Zn-OH, Co-OH, the NaOH produced ZnCo-LDH microparticles, and even the benchmark catalyst of RuO at high current density. Characterization experiments indicated that the outstanding electrocatalytic activity can be ascribed to the nanosheet-induced surface area effect, excellent electronic conductivity, and the coupling effect between Zn and Co in the material. This work offers a facile and environmental-friendly method for synthesising LDH nanosheets bearing enhanced oxygen evolution reaction activity.
在电化学可持续化学领域，用廉价且储量丰富的金属催化剂替代稀有且昂贵的贵金属催化剂是一项极具吸引力但又具有挑战性的任务。在此，通过一步室温反应，以2-甲基咪唑作为双功能碱源（OH）和形貌控制试剂，简便地合成了双金属锌-钴层状双氢氧化物纳米片（ZnCo-LDH NS）。机理研究表明，2-甲基咪唑的弱有机碱在水/乙醇中诱导OH的缓慢释放是形成LDH纳米片的控制因素。修饰在玻碳电极上的ZnCo-LDH NS在1.0 M KOH中进行析氧反应时，在10 mA cm时的过电位为385 mV，塔菲尔斜率为108 mV dec，在高电流密度下优于相应的单金属氧化物Zn-OH、Co-OH、NaOH制备的ZnCo-LDH微粒，甚至优于基准催化剂RuO。表征实验表明，优异的电催化活性可归因于纳米片诱导的表面积效应、优异的电子导电性以及材料中Zn和Co之间的耦合效应。这项工作为合成具有增强析氧反应活性的LDH纳米片提供了一种简便且环境友好的方法。
