The effect of urea on microstructures of Ni₃S₂ on nickel foam and its hydrogen evolution reaction

The effects of urea concentration on microstructures of Ni₃S₂formed on nickel foam and its hydrogen evolution reaction were investigated. The Ni₃S₂ nanosheets with porous structure were formed on nickel foam during hydrothermal process due to low urea concentration. While high urea concentration facilitated the forming of Ni₃S₂ nanotube arrays. The resulting Ni₃S₂ nanotube arrays exhibited higher catalytic activity than Ni3S2nanosheets for hydrogen evolution reaction. This was mainly attributed to a fact that Ni₃S₂ nanotube arrays facilitated diffusion of electrolyte for hydrogen evolution reaction.