Molten salt electrolysis method to achieve Ni/MoS2 with activity sulfur enhance the hydrogen evolution reaction performance under alkaline condition
By Zhang, Shuang; Fang, Cheng; Liu, Yu-hui; Lin, Sheng; Lin, Shan; Zeng, Rong; Wei, Qiang-lin; Zeng, Lin-sheng; Chen, Yi-fu; Na, Bing
Published in Surfaces and Interfaces
Surfaces and Interfaces
2020
Abstract
The main problem in the application of molybdenum disulfide (MoS2) in hydrogen evolution reaction (HER) is difficult to optimize the active site and promote the charge transfer. The decoration of Ni can improve the intrinsic activity and increase the number of active sites of MoS2 efficiency. An electrode of Ni/MoS2 nanosheets or nanoflowers on carbon fiber cloth is designed via a facile one-pot molten salt electrolysis method. The amount of doped Ni was controllable during the molten salt electrolysis process. Two specially structures of nanosheets and nanoflowers were compared to confirm the effect by structure. Benefiting from Ni decoration and its unique crystal structure, the Ni/MoS2 electrode exhibits excellent electrocatalytic performance in alkaline solution (1 M KOH). As a result, the designed electrocatalyst of Ni/MoS2 nanosheets shows the best catalytic performance with low overpotentials (109.0 mV for the current density of 10.0 mA cm?2) and the small Tafel slope (41.2 mV dec?1). Test results of electrocatalytic hydrogen evolution and density functional theory (DFT) calculation revealed that Mo was substituted by Ni. S near the top position is activated by two doping Ni atoms to adsorb H. The Hydrogen is adsorbed on the surface with the lowest free energy of adsorption ?GH* (?GH*= 0.13). When the S atom is at the far end, the free energy of adsorption increases. These findings open an effective and propagable strategy for nanostructure HER catalysts synthesis.