Effect of pore orientation on the catalytic performance of porous NiMo electrode for hydrogen evolution in alkaline solutions

Abstract

Porous NiMo alloys with Mo content of 5 at.% were fabricated by freezing casting method. The pores are elongated, and the media pore size is 8.1 μm. The electrocatalytic activity of the synthesized NiMo alloy foam as cathodes for hydrogen evolution reaction (HER) in 6.0 M potassium hydroxide solution was investigated. Results show that the electrodes which pore orientation is parallel to the hydrogen overflow direction present higher electrocatalytic activity than the electrodes with pore orientation perpendicular to the hydrogen overflow direction. The Tafel slope is 94 and 117 mV dec−1, respectively at a current density of 10 mA/cm2 at room temperature.