The Heterojunction of Ni and Co9S8 was Synthesized and Anchored on Carbon Nanotubes to Improve the Performance of Water Electrolysis

Developing durable, low-cost water electrolysis catalysts plays a critical role in solving clean energy problems. Herein, we synthesized Ni/Co9S8@CNT micro flower comprising Ni/Co9S8 mesoporous nanosheets and carbon nanotubes (CNT). HRTEM images indicate that the Ni/Co9S8@CNT micro flower contains abundant Ni/Co9S8 heterojunctions. The band structure and coupling effect of the Ni/Co9S8 heterostructure optimizes the transfer of electrons, thus the synergistic hybrid effectively improves conductivity and electrocatalytic performance. Therefore, Ni/Co9S8@CNT shows good evolution reaction (OER) and hydrogen evolution reaction (HER) performance in an alkaline environment. Specifically, at a current density of 10 mA cm−2, the overpotential of OER is 289 mV, and the overpotential of HER is 228 mV. The Tafel slope is 69 mV dec−1. In addition, Ni/Co9S8@CNT in alkaline electrolyte only loses 10% of its activity after working for 10 h at a current density of 10 mA cm−2. These results indicate that composite materials composed of transition metal sulfides and highly conductive carbon materials are a good choice for low-cost electrocatalysts. Synthesize the heterojunction of metal Ni and Co9S8 and anchor it on the CNT to improve the performance of OER and HER.