Two Dimensional Ir‐Based Catalysts for Acidic OER

Abstract

Electrochemical water splitting in acidic media is one of the most promising hydrogen production technologies, yet its practical applications in proton exchange membrane (PEM) water electrolyzers are limited by the anodic oxygen evolution reaction (OER). Iridium (Ir)‐based materials are considered as the state‐of‐the‐art catalysts for acidic OER due to their good stability under harsh acidic conditions. However, their activities still have much room for improvement. Two‐dimensional (2D) materials are full of the advantages of high‐surface area, unique electrical properties, facile surface modification, and good stability, making the development of 2D Ir‐based catalysts more attractive for achieving high catalytic performance. In this review, first, the unique advantages of 2D catalysts for electrocatalysis are reviewed. Thereafter, the classification, synthesis methods, and recent OER achievements of 2D Ir‐based materials, including pure metals, alloys, oxides, and perovskites are introduced. Finally, the prospects and challenges of developing 2D Ir‐based catalysts for future acidic OER are discussed.

Thermal‐Driven Orderly Assembly of Ir‐atomic Chains on α‐MnO2 with Enhanced Performance for Acidic Oxygen Evolution

“…Different values of the Tafel slope imply different rate‐determining steps, with smaller Tafel slopes indicating that the rate‐determining step is at the end of the multi‐electron transfer reaction, which is usually a sign of a good electrocatalyst. Next, the Tafel slope of IrCeMnO@Ir NRs (∼58 mV dec −1 ) (Figure 8d) is lower than that of IrMnO@Ir (∼64 mV dec −1 ) and commercial IrO 2 (∼83 mV dec −1 ), which suggests that the OER kinetics has a faster electron transport rate and higher conductivity/electrocatalytic activity [32] …”

“…Next, the Tafel slope of IrCeMnO@Ir NRs (~58 mV dec À 1 ) (Figure 8d) is lower than that of IrMnO@Ir (~64 mV dec À 1 ) and commercial IrO 2 (~83 mV dec À 1 ), which suggests that the OER kinetics has a faster electron transport rate and higher conductivity/electrocatalytic activity. [32] Figure 8e shows the EIS plots performed of as-synthesized IrCeMnO@Ir, IrMnO@Ir NRs, and commercial IrO 2 at ~1.45 V (vs. RHE). Notably, the Rct (charge transfer resistance) of IrCeM-nO@Ir was about 6.8 Ω, which was significantly lower than that of the synthesized IrMnO@Ir and commercial IrO 2 (Table S3).…”

Recent Developments in Two-Dimensional Carbon-Based Nanomaterials for Electrochemical Water Oxidation: A Mini Review

“…Currently, Ir−based and Ru−based materials are known as the most advanced and efficient OER electrocatalysts [32,33]. Nevertheless, their restricted multifunctional performance and high cost limit their large−scale applications for OER [34,35].…”

Ru/Ir‐Based Electrocatalysts for Oxygen Evolution Reaction in Acidic Conditions: From Mechanisms, Optimizations to Challenges

“…[ 12–14 ] Numerous electrolysis cell devices can convert intermittent renewable energy sources such as solar, wind and tidal energy into H 2 and O 2 using water splitting technology, which can be reconverted to electricity in a fuel cell when needed. [ 15,16 ] The technology is environmentally friendly, utilizes abundant raw materials, and is crucial for the development of hydrogen energy. [ 15–19 ] Water splitting consists of two half‐reactions, the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER).…”