2-Methylimidazole directed ambient synthesis of zinc-cobalt LDH nanosheets for efficient oxygen evolution reaction

• Published in: Journal of colloid and interface science Vol. 565; pp. 351 - 359
• Main Authors: Qiu, Chunyu, Cai, Fuxian, Wang, Yuan, Liu, Yijun, Wang, Qingxiang, Zhao, Chuan
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.04.2020
• Subjects: 2-methylimidazole; Ambient synthesis; ambient temperature; catalysts; catalytic activity; cobalt; electrochemistry; ethanol; glassy carbon electrode; green chemistry; microparticles; Nanosheet; nanosheets; oxides; Oxygen evolution; oxygen production; potassium hydroxide; Reaction; sodium hydroxide; surface area; zinc; Zinc-cobalt LDH; Oxygen evolution; Ambient synthesis; Zinc-cobalt LDH; Nanosheet; Reaction; 2-methylimidazole
• ISSN: 0021-9797; 1095-7103; 1095-7103
• DOI: 10.1016/j.jcis.2019.12.070

[Display omitted] 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−2 and a Tafel slope of 108 mV dec−1 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 RuO2 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 Zn2+ and Co2+ in the material. This work offers a facile and environmental-friendly method for synthesising LDH nanosheets bearing enhanced oxygen evolution reaction activity.