Electrochimica Acta, Vol.211, 900-910, 2016
3D multi-structural porous NiAg films with nanoarchitecture walls: high catalytic activity and stability for hydrogen evolution reaction
The design of efficient and stable electrocatalysts for hydrogen evolution reaction ( HER) is essential to the sustainable hydrogen production by water electrolysis. The catalytic activity of electrocatalysts can be significantly improved by increasing the effective active area. The 3D multi-structural micro/nanoporous NiAg films with nanoarchitecture walls were directly electrodeposited by hydrogen bubble template method. The catalytic activity and durability of NiAg films for HER were studied in 6 M KOH solution based on the adjustment of the surface roughness and the wettability. It was found that the walls of porous NiAg films were composed of nanoparticles and nanochannels. However, the closely arranged microparticles were only observed in the pore walls of Ni films. The thicknesses of NiAg films (>20 mu m) were much larger than those of Ni (7 mu m) and Ag film (4 mu m). The 3D multi-structural porous NiAg films exhibited better catalytic activity than Ni or Ag film. HER on all films was controlled by the electrochemical adsorption step of hydrogen atoms (H) to form MHads. The surface roughness of NiAg films was up to 4352 and much higher than those (32 and 273) of Ni and Ag films. Therefore, the effective active areas for H adsorption on NiAg films increased, which led to the improvement of HER activity. In addition, NiAg films possessed good long-term durability. The cell voltages of water electrolysis on NiAg films were much lower than those on Ni and Ag films. It was ascribed to high catalytic activity and rapid bubble separation on 3D micro/nanoporous NiAg films. (C) 2016 Elsevier Ltd. All rights reserved.