The well-established proton exchange membrane (PEM)-based water electrolysis, which operates under acidic conditions, possesses many advantages compared to alkaline water electrolysis, such as compact design, higher voltage efficiency, and higher gas purity. However, PEM-based water electrolysis must be improved by the low efficiency, instability, and high cost of anodic electrocatalysts for the oxygen evolution reaction (OER).
Many OER electrocatalysts are prone to dissolution and surface structure transformation under the oxidizing OER potentials in the harsh acidic environment, finally leading to a drastic decrease in catalytic performance.
A new study by the team at the Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences (CAS) summarizes, classifies, and discusses the recently reported acidic OER electrocatalysts. They conducted a series of research on OER electrocatalysis by combining experiments and theoretical calculations.
Much focus was put on the OER mechanisms, which may be divided into two groups based on where oxygen atoms come from: the adsorbate evolution mechanism and the lattice oxygen oxidation mechanism.
It was thoroughly discussed how acidic OER electrocatalyst activity and stability relate. The scientists additionally suggested a stability test strategy to assess the loss of intrinsic activity.
The utilization of carbon-based materials was one of the unresolved concerns and current development challenges of the mentioned acidic OER electrocatalysts. Also, there were some suggestions for synthesizing high-performance acidic OER electrocatalysts for PEM-based water electrolysis.