Combined Rotating Disk Slurry Electrodeposition–Spontaneous Galvanic Displacement for Pt-M (M = Co, Ni, and Cu) Catalyst Synthesis for the Oxygen Reduction Reaction in Alkaline Media

Abstract

Platinum-modified first-row transition-metal catalyst (M = Ni, Co, and Cu) nanoparticles on a carbon black Vulcan XC-72R (CBV) support were synthesized using rotating disk slurry electrodeposition (RoDSE) followed by spontaneous galvanic displacement (SGD) reactions. These RoDSE–SGD catalysts were evaluated for the oxygen reduction reaction (ORR) in 0.1 M KOH using rotating disk electrode techniques. The Ni and Co RoDSEs were done by using an electrochemical applied potential of −0.75 V versus the RHE and for Cu, −0.80 V versus the RHE using a CBV slurry solution containing 0.1 M KClO4. These metal nanoparticles on CBV (M/CBV) catalysts were modified with a Pt precursor via a spontaneous galvanic displacement (SGD) reaction, producing a Pt-M/CBV material to catalyze the ORR in an alkaline medium. High-resolution scanning transmission electron microscopy (HR-STEM) analysis indicates that the PtM/CBV samples include M clusters and Pt single atoms. The ORR characterization measurements were done under a controlled temperature (25.0 °C) and with a mass loading of 100 μg/cm2 on a glassy carbon (GC) rotating disk electrode at 1600 rpm. The PtCo/CBV showed the highest ORR mass activity of 0.741 A/mgPt at 0.90 V versus the reversible hydrogen electrode (RHE) compared with commercial Pt/CBV. The M/CBV RoDSE catalysts were also tested for the oxygen evolution reaction (OER), and Ni/CBV provided the lowest overpotential of 450 mV at 10 mA/cm2 disk in 0.1 M KOH.

Uranium electrodeposition at boron-doped diamond electrodes

“…The primary challenge encountered in uranium electrodeposition in aqueous media is the hydrogen evolution reaction (HER) [23]. Despite the underexplored nature of electrodeposition methodologies in the HER potential region, our previous works demonstrated the electrodeposition of various metals in a potential window associated with high current pro les related to the HER [29,30]. Given these considerations, and to comprehensively explore the in uence of electrodeposition potential on the features of our U-lms, [23] we conducted an in-depth atomic force microscopy (AFM) study to assess their morphology, topography, and roughness.…”