Hydrogen Evolution Reaction Performance of Ni–Co-Coated\nGraphene-Based 3D Printed Electrodes

Abstract

Additive manufacturing\nhas been a very promising topic in recent\nyears for research and development studies and industrial applications.\nIts electrochemical applications are very popular due to the cost-effective\nrapid production from the environmentally friendly method. In this\nstudy, three-dimensional (3D) printed electrodes are prepared by Ni\nand Co coatings in different molar ratios. Different Ni/Co molar ratios\n(<i>x</i>:<i>y</i>) of the Ni/Co/<i>x</i>:<i>y</i> alloys are prepared as 1:1, 1:4, and 4:1 and\nthey are named Ni/Co/1:1, Ni/Co/4:1, and Ni/Co/1:4, respectively.\nAccording to the results, when the 3D electrode samples are coated\nwith Ni and Co at different molar ratios, the kinetic performance\nof the NiCo-coated 3D electrode samples for hydrogen evolution reaction\nis enhanced compared to that of the uncoated 3D electrode sample.\nThe results indicate that the Ni/Co/1:4-coated 3D electrode has the\nhighest kinetic activity for hydrogen evolution reactions (HERs).\nThe calculated Tafel′s slope and overpotential value (η₁₀) for HER are determined as 164.65 mV/dec and 101.92 mV,\nrespectively. Moreover, the Ni/Co/1:4-coated 3D electrode has an 81.2%\nhigher current density than the other electrode. It is observed that\nthe 3D printing of the electrochemical electrodes is very promising\nwhen they are coated with Ni–Co metals in different ratios.\nThis study provides a new perspective on the use of 3D printed electrodes\nfor high-performance water electrolysis.