Modulating metal–organic frameworks for catalyzing acidic oxygen evolution for proton exchange membrane water electrolysis

Abstract

Proton exchange membrane (PEM) water electrolysis represents one of the most promising technologies to achieve green hydrogen production, but currently its practical viability is largely affected by the slow reaction kinetics of the anodic oxygen evolution reaction (OER) in an acidic environment. While noble metalbased catalysts containing iridium or ruthenium are excellent catalysts for the acidic OER, their practical use in PEM electrolyzers is hindered due to their low abundance and high cost. Most recently, metal-organic frameworks (MOFs) have been demonstrated as a perfect platform to facilitate the design of acidic OER catalysts with both high efficiency and cost-effectiveness. Here, we provide a timely and comprehensive overview of the recent progress on MOFbased acidic OER catalysts. The fundamental mechanisms of the acidic OER are first introduced, followed by a summary of the development of pristine MOFs and MOF derivatives as acidic OER catalysts. Importantly, a number of catalyst design strategies are discussed aiming at improving the acidic OER catalytic performance of MOF-based candidates. The integration of MOF-based catalysts into real PEM water electrolyzers is also included. Finally, future research directions are provided to achieve better MOF-based catalysts operational in acidic environments and PEM devices.

New Undisputed Evidence and Strategy for Enhanced Lattice‐Oxygen Participation of Perovskite Electrocatalyst through Cation Deficiency Manipulation

“…Therefore, tremendous efforts have been made to develop non‐noble metal‐based alternatives that are competitively efficient. [ 7–9 ]…”

“…Therefore, tremendous efforts have been made to develop non-noble metal-based alternatives that are competitively efficient. [7][8][9] Among various candidates, ABO 3 -type perovskite oxides, where A and B is respectively a rare-earth or alkaline-earth metal and a transition metal, are promising OER electrocatalysts thanks to their low cost, easy synthesis, and high catalytic activity. [10][11][12] In particular, by leveraging their compositional flexibility, which allows elemental doping or substitution at all the A-, B-, and O-sites, the crystalline structure and electronic structure of perovskite oxides can be fine-tuned, providing plenty of room for the rational design of better OER catalysts.…”

High Selectivity Electrocatalysts for Oxygen Evolution Reaction and Anti-Chlorine Corrosion Strategies in Seawater Splitting

“…Both reactions need highly efficient electrocatalysts to overcome energy consumption overpotentials. After a wide variety of research efforts and tremendous advancements, researchers have successfully developed many excellent electrocatalysts for OERs and HERs, which can significantly promote the application of water splitting [13][14][15][16][17][18][19][20]. However, electrocatalysts that are both stable and highly active are still insufficient to the task, so direct electrolysis of seawater to generate H 2 remains challenging.…”

Phosphorus-Doped Graphene Electrocatalysts for Oxygen Reduction Reaction

“…The conversion efficiency of converting chemical energy into electrical energy is many folds higher than that of conversion of chemical energy into thermal (e.g., combustion) or kinetic energies (e.g., modern IC engines). Accordingly, great attention has been given to the study of fuel cells and metal-air batteries as the next-generation energy conversion techniques because these devices can directly convert chemical energy into electric energy with nearly zero carbon footprint [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. In fuel cells and metal-air batteries, the electrochemical reactions, in particular, the oxygen reduction reaction (ORR) in the cathode, determine the performance [ 10 , 11 ].…”