Optimizing Platinum Location on Nickel Hydroxide Nanosheets to Accelerate the Hydrogen Evolution Reaction

Rational electrode design is crucial to promote the performance of the hydrogen evolution reaction (HER) via further enhancing the activity, stability, and utilization of platinum (Pt) in an alkaline electrolyte. Herein, a binder-free low-Pt-content HER electrode, Pt (∼20 μg cm^-2) decorated on nickel hydroxide grown on nickel foam (Pt-Ni(OH)₂-2h-NF20), is fabricated at near room temperature in a test tube. To lower the ohmic resistance, for the first time, the Pt nanoparticles were location-selectively anchored on the bottom of height-controlled vertical Ni(OH)₂ nanosheets via utilizing the mass transfer resistance of the dense Ni(OH)₂ film for chloroplatinate. Furthermore, the excellent mass transfer, high specific surface area of Pt, synergistic effect between Pt with Ni(OH)₂, and stable structure together prompt the resulting electrode with a special structure to exhibit superior HER electrocatalytic activity and stability in 1 M KOH. Typically, this electrode reaches a current density of 35.9 mA cm^-2 at an overpotential of 100 mV, which is over 8 times higher than that of commercial Pt/C, and the overpotential only increases by 20 mV at 100 mA cm^-2 over 150,000 s of stability test. Benefiting from the simple fabrication process, the electrode with an area of 840 cm² was successfully prepared with a steady overpotential of 370 mV at 1000 mA cm^-2 and increased potential of 23 mV over 50 h of stability test.