Fabrication of cost-effective Ni-based metallic composite columnar catalyst on stainless steel electrode via stress release-assisted electrochemical micro-machining for water electrolyzer.

Abstract

This study investigates the preparation of NiCoCrMoW multicomponent alloy metallic composite on stainless steel mesh substrates via electrochemical micro-machining to fabricate columnar catalyst for enhanced hydrogen evolution reaction (HER) performance. Two simple steps of electrodeposition have successful prepared a Ni-NiCoCrMoW micro-metallic composite which are composed of the Ni anchor layer and the outer columnar grain structure layer with high internal stress. Designing the electrochemical micro-machining process that release the internal stresses by cathodic polarization in 0.5 mol/L H₂SO₄, triggers spontaneous deformation and structural changes in the crystalline and the formation of micro-cracks, thus the electrochemically active surface area and the high electrocatalytic sites are increased. Finally, the columnar catalyst exhibits excellent HER performance across acidic, neutral, and alkaline environments, achieving an overpotential of 57 mV at a current density of 10 mA cm^-2 in 0.5 mol/L H₂SO₄. Additionally, electrochemical stability testing demonstrate that the electrodes maintain catalytic activity for over 200 h. This novel electrochemical fabrication process integrating stress engineering with 4D printing principles provides a scalable, cost-effective method for fabricating high-performance HER catalysts, with significant potential for industrial hydrogen production.