Iridium–Nickel Nanoparticle-Based Aerogels for Oxygen Evolution Reaction

Abstract

Iridium is considered the state-of-the-art electrocatalyst for the oxygen evolution reaction (OER) in acidic media owing to its considerably high activity and stability, yet it is a raw material that is expensive and rare. Here we present a synthesis of a bimetallic hollow aerogel structure based on iridium and nickel prepared by a very simple and environmentally friendly method. Our electrocatalyst was evaluated for the OER in a single electrolysis cell, and it showed an improvement in electrocatalytic performance over time, reaching the current density of commercial IrO 2 after 500 h of the stability test, despite half the catalyst loading. Our innovative synthesis approach provides the flexibility to tailor and improve the aerogel structures for other electrochemical devices as well, for example, photoelectrolysis, sensors, and more. In addition, we believe that this study can lead to a better understanding of the fundamental behavior of bimetallic electrocatalysts consisting of mixed compositions with transition metals.

Gold-Doped Cobalt–Nickel Sulfide Nanosheets for Oxygen Evolution Reaction

“…As shown in Figure and Figure S2, the binding energies at 885.7 and 873.0 eV in the high-resolution spectrum of Ni 2p correspond to the spin–orbit splitting peaks of 2p 3/2 and 2p 1/2 of Ni 2+ . The peaks at 780.8 and 796.2 eV of Co 2p can be attributed to the spin–orbit splitting peaks of 2p 3/2 and 2p 1/2 for Co 2+ . The spin–orbit coupled cleavage peaks of 2p 3/2 and 2p 1/2 for S 2– are observed at 162.2 and 163.4 eV, respectively .…”

“…12 The peaks at 780.8 and 796.2 eV of Co 2p can be attributed to the spin− orbit splitting peaks of 2p 3/2 and 2p 1/2 for Co 2+ . 15 The spin− orbit coupled cleavage peaks of 2p 3/2 and 2p 1/2 for S 2− are observed at 162.2 and 163.4 eV, respectively. 41 The successful loading of Au was also proven in XPS, with the fine spectrum of Au at 84.2/87.4 eV and 88.4/91.7 eV separately assigning to the spin−orbit splitting peaks of 4f 7/2 /4f 5/2 for Au 0 and Au 3+ .…”

“…The transition metal synergistic effect influences the valence distribution, structure, and electron transport capacity of the materials. 14,15 Based on the synergistic catalysis of Ni and Co, the synthesized core−shell Co 3 O 4 @CoNiS exhibiting enhanced specific capacity and high energy density, 16 the layered Cu 2 S NRs@CoS improved the electrolytic water performance by the synergistic effect of Cu and Co. 17 in optimizing OER performance. 21−23 For example, Chen and co-workers doped Ni 2 P with Fe to enhance the interaction between the adsorbate and the catalyst surface, 24 and the introduction of Cu into the IrO 2 system resulted in an increased OER activity in acidic, neutral, and basic solutions.…”

“…The transition metal synergistic effect influences the valence distribution, structure, and electron transport capacity of the materials. , Based on the synergistic catalysis of Ni and Co, the synthesized core–shell Co 3 O 4 @CoNiS exhibiting enhanced specific capacity and high energy density, the layered Cu 2 S NRs@CoS improved the electrolytic water performance by the synergistic effect of Cu and Co . In addition, plenty of experimental examples show that doping is an important tool for improving the OER performance of electrocatalysts. − Doping species and their doping ratios can be reasonably changed to adjust the energy difference between the d-band level and the Fermi level to a suitable position, and the selection and scaling of suitable dopants are important factors in optimizing OER performance. − For example, Chen and co-workers doped Ni 2 P with Fe to enhance the interaction between the adsorbate and the catalyst surface, and the introduction of Cu into the IrO 2 system resulted in an increased OER activity in acidic, neutral, and basic solutions .…”

Strong Metal‐Support Interactions in ZrO2‐Supported IrOx Catalyst for Efficient Oxygen Evolution Reaction

“…[5] One of the best ways to reduce Ir usage is to boost catalyst utilization in the CCM. This can be achieved by increasing Ir dispersion using high surface area supports, [6] use of different Ir morphologies, [7][8][9][10][11][12][13][14][15][16][17][18] and use of promoters. [19][20][21][22][23] Among the available options, using supported catalysts offers an appealing solution to meet the demands of practical large-scale applications while simultaneously reducing the amount of precious metal needed for catalyst synthesis.…”