The Structure Evolution Mechanism of Ni Films Depending on Hydrogen Evolution Property During Electrodeposition Process
- PDF / 3,092,300 Bytes
- 8 Pages / 593.972 x 792 pts Page_size
- 8 Downloads / 305 Views
The Structure Evolution Mechanism of Ni Films Depending on Hydrogen Evolution Property During Electrodeposition Process XIANGTAO YU and ZHANGFU YUAN Hydrogen evolution property is an important factor to regulate the surface structure of the electrodeposited Ni film. In this work, the dependence of current density on hydrogen evolution property is researched. The structure evolution mechanism of the Ni film depending on current density is analyzed in terms of the hydrogen evolution characteristic. It is found that the surface structure of the Ni film from compact to porous structure could be achieved by adjusting the electrodeposition current density. At low current density (less than 0.07 A cm2), the current efficient of hydrogen evolution is very weak. Ni electrodeposition is the main reaction, so compact Ni film is formed. At high current density (higher than 0.3 A cm2), hydrogen evolution reaction is enhanced with the increase of current density. At this time, there are plenty of bubbles which can act as templates. As a result, porous Ni film is electrodeposited. However, when the current density is lower than 0.7 A cm2, dish-like pore with large diameter is formed due to the large break-off diameter and the long resident time of the hydrogen bubble. And honeycomb-like pore with small diameter is formed at current density larger than 1 A cm2, because of reduced break-off diameter and resident time of the hydrogen bubble. Porous film with uniform structure is electrodeposited at 1 A cm2, which possesses the higher catalytic activity for hydrogen evolution. https://doi.org/10.1007/s11663-019-01512-4 The Minerals, Metals & Materials Society and ASM International 2019
I.
INTRODUCTION
THREE-DIMENSIONAL (3D) porous metal films are widely used in the fields of electrochemical conversion and energy storage devices due to their large specific surface area and good wettability.[1–3] The dynamic bubble template (DBT) method is considered as the most facile and excellent method to prepare the 3D porous metal films.[4,5] Various porous metal and alloy films were prepared by this method.[6–9] However, the pore wall thickness and pore distribution are not uniform,[10,11] and it is difficult to regulate the porous structure. Generally, it is believed that the surface structure of porous films mainly depends on the hydrogen evolution property (including hydrogen evolution rate and bubble behavior).[12–15] Ye et al.[14] established a stack model of porous structure, in which big bubbles with large diameter were formed due to the coalescence of small XIANGTAO YU and ZHANGFU YUAN are with the Collaborative Innovation Center for Steel Technology, University of Science and Technology Beijing, Beijing 100083, China. Contact e-mail: [email protected] Manuscript submitted November 2, 2018.
METALLURGICAL AND MATERIALS TRANSACTIONS B
bubbles with electrodeposition time, and large pores covered the small pores. Kim et al.[16] found a rough substrate could prevent the coalescence of hydrogen bubbles, thereby reducing the bubble break-off diam
Data Loading...
