The Role of Electrocatalysts in the Development of Gigawatt-Scale PEM Electrolyzers

Abstract

Electrocatalysts are nanomaterials of paramount importance within water electrolyzers, because they facilitate the electron transfer between reactants and electrode, enabling the chemical transformation of water into hydrogen and oxygen. In this Perspective, recent findings in electrocatalyst development for the next generation of polymer electrolyte membrane (PEM) water electrolyzers at scale are discussed. We discuss opportunities to create catalyst architectures, the importance to demonstrate electrode manufacturing tools, and how useful advanced characterization methods shall, in the short term, allow large-scale deployment of water splitting devices with higher efficiency, acceptable durability, and low cost. We envision next-generation PEM cells permitting a transformational change in the chemical industry by the manufacturing of low-cost hydrogen.

Unveiling the reconstructed active phase of Ni3Se2model for water splitting

“…[1][2][3] The development of many advanced energy-conversion technologies, such as rechargeable metal air cells, regenerative fuel cells, and water splitting devices, rely heavily on the exploration of catalytic materials involved in these electrochemical processes and related performance enhancements, such as hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). [4][5][6][7][8] However, most excellent electrocatalysts at present are Pt-based materials for HER, and Ir-or Ru-based materials for OER, all belonging to precious metals, which cannot be effectively used in industrialization due to their limited storage and high cost. 9,10 Various 3d-transition metal-based compounds have been gradually developed to replace these precious catalysts, and their electrocatalytic performances have been able to approach or even surpass that of the current precious metal system catalysts.…”

Investigation of Water Oxidation at IrO2 Electrodes in Nafion-Based Membrane Electrode Assemblies Using Impedance Spectroscopy and Distribution of Relaxation Times Analysis

“…However, large loadings of iridium-based catalysts (>1 mg Ir cm −2 ) are typically required to achieve long-term operation with minimal voltage losses, decreasing the scalability of electrolyzers and increasing cell manufacturing capital costs. 3,21 Recent power efficiency estimates have indicated that a 10-fold improvement in the performance of iridium-based catalyst layers is required for the scalable deployment of PEM-based electrolyzers. 21 As such, developing efficient and stable anode catalyst layers with limited iridium use is critical to meet these demands.…”

“…This design can produce hydrogen devoid of carbon emissions, which in turn can be coupled to carbon-capture technologies to produce synthetic precursors from atmospheric carbon dioxide, used as a fuel directly to provide heat or electrical power, or be utilized for ammonia production. Further, with the recent decline in renewable energy prices, the increased renewable energy capacity globally, and recent global mandates to develop a hydrogen-based economy, implementation of cost-effective water electrolyzers for green hydrogen is becoming more of a reality. , …”

“…At the anode, acidic water oxidation occurs via the following half-reaction .25ex2ex 2 H 2 O ↔ 4 H + + 4 e − + O 2 false( normalg false) , E 0 = 1.229 V v s R H E The anode catalyst layer often consists of an iridium oxide-based catalyst and ionomer to perform the oxygen-evolving reaction (OER) due to its high stability to corrosion under the acidic oxidizing conditions and high catalytic activity toward the OER under acidic conditions. However, large loadings of iridium-based catalysts (>1 mg Ir cm –2 ) are typically required to achieve long-term operation with minimal voltage losses, decreasing the scalability of electrolyzers and increasing cell manufacturing capital costs. , Recent power efficiency estimates have indicated that a 10-fold improvement in the performance of iridium-based catalyst layers is required for the scalable deployment of PEM-based electrolyzers . As such, developing efficient and stable anode catalyst layers with limited iridium use is critical to meet these demands.…”

“…Further, with the recent decline in renewable energy prices, the increased renewable energy capacity globally, and recent global mandates to develop a hydrogen-based economy, implementation of cost-effective water electrolyzers for green hydrogen is becoming more of a reality. 3,4 Water electrolysis can be performed in different configurations, such as in alkaline cells, polymer electrolyte membrane cells, and solid oxide cells. 5 Alkaline electrolyzers are technologically mature, utilizing abundant materials and exhibiting long cell lifetimes of ca.…”