ZIF-67-Derived Porous Carbon Nanosheets Decorated with Co Nanoflakes As Bifunctional Electrocatalysts for Overall Water Splitting
Haixia Zhang, Wenyuan Dai, Ru Liu, Junying Xiang, Yanhui Song, Ying Hou, Wei Hong, Peizhi Liu, Bingshe Xu, Jianguo Liang, Junjie Guo
Abstract
ZIF-67-derived Co–N–C catalysts exhibit efficient water-splitting performance and thus have attracted intense research interest. However, the serious Co agglomeration and loss of most N atoms due to high-temperature pyrolysis limit the further improvement of their electrocatalytic performance. Herein, we report a ZIF-67-derived 2D porous N-doped carbon nanosheet decorated with a Co nanoflake catalyst (Co@NC/CC-500) for OER and HER by a facile pyrolysis method at a low temperature of 500 °C. Benefiting from the ultrahigh N doping (12 atom %) and uniformly dispersed Co nanoflakes on 2D porous carbon nanosheets, which lead to a high content of Co–N active sites, the Co@NC/CC-500 catalyst exhibits outstanding performance toward the HER and OER with overpotentials of 95 and 183 mV at 10 mA cm –2 in 1 M KOH, respectively. Furthermore, the alkaline water electrolyzer using Co@NC/CC-500 as the cathode and anode catalysts can achieve a current density of 10 mA cm –2 at a cell voltage of 1.52 V. This special low-temperature production method may be extensively utilized to create precisely defined monometal or bimetal nanoflakes decorated on 2D porous N-doped carbon nanosheets for diverse electrochemical energy applications.