Carbon-Based Composites as Electrocatalysts for Oxygen Evolution Reaction in Alkaline Media

Abstract

This review paper presents the most recent research progress on carbon-based composite electrocatalysts for the oxygen evolution reaction (OER), which are of interest for application in low temperature water electrolyzers for hydrogen production. The reviewed materials are primarily investigated as active and stable replacements aimed at lowering the cost of the metal electrocatalysts in liquid alkaline electrolyzers as well as potential electrocatalysts for an emerging technology like alkaline exchange membrane (AEM) electrolyzers. Low temperature electrolyzer technologies are first briefly introduced and the challenges thereof are presented. The non-carbon electrocatalysts are briefly overviewed, with an emphasis on the modes of action of different active phases. The main part of the review focuses on the role of carbon–metal compound active phase interfaces with an emphasis on the synergistic and additive effects. The procedures of carbon oxidative pretreatment and an overview of metal-free carbon catalysts for OER are presented. Then, the successful synthesis protocols of composite materials are presented with a discussion on the specific catalytic activity of carbon composites with metal hydroxides/oxyhydroxides/oxides, chalcogenides, nitrides and phosphides. Finally, a summary and outlook on carbon-based composites for low temperature water electrolysis are presented.

What is Next in Anion‐Exchange Membrane Water Electrolyzers? Bottlenecks, Benefits, and Future

“…As an example, the implementation at the anode side of PGM-free OER electrocatalysts known to be highly active in liquid alkaline environment has hitherto resulted in low AEM-WE performance. [116,[125][126][127] Several studies concluded that a dilute KOH feed (0.01-1.0 m KOH) is critical to reaching a high performance with PGMfree anodes in AEM-WE. [52,125,[127][128][129] Figure 6A is an example of the effect of the anolyte feed nature on the AEM-WE performance, in otherwise fixed conditions and for a same MEA, comprising a CuCoO x anode.…”

“…While the development of novel CRM‐free HER and OER electrocatalysts specifically designed for high‐pH environment is critically needed, their rational integration in the MEA of an AEM‐WE fed and operating with pure water will likely be as critical. As an example, the implementation at the anode side of PGM‐free OER electrocatalysts known to be highly active in liquid alkaline environment has hitherto resulted in low AEM‐WE performance [116,125–127] …”

Zirconia Toughened Alumina-Based Separator Membrane for Advanced Alkaline Water Electrolyzer

“…On the contrary, alkaline water electrolyzers (AWEs) exhibit higher durability, simplicity, robust performance, low capital cost, and adequate compatibility with non-noble metal catalysts [ 21 , 22 , 23 , 24 , 25 ]. AWEs are in commercial use for quite a long time and are considered a mature technology [ 26 ].…”

Studying Performance and Kinetic Differences between Various Anode Electrodes in Proton Exchange Membrane Water Electrolysis Cell

“…PEMWE can be operated at a high current density that enables high hydrogen production rate [ 23 , 24 , 25 , 26 ], and quickly starts or stops, which fits well with intermittent renewable energy sources [ 27 ]. Therefore, a lot of researchers have paid attention to PEMWE technology and targeted at its commercialization, due to its advantages compared to other hydrogen production techniques [ 28 , 29 , 30 , 31 , 32 ].…”