The proven water electrolysis based on a proton exchange membrane (PEM), which operates under acidic conditions, has many advantages over alkaline water electrolysis, such as compact design, higher voltage efficiency and higher gas purity. However, PEM-based water electrolysis needs to be improved due to the low efficiency, instability and high cost of anodic electrocatalysts for the oxygen evolution reaction (OER).

Many OER electrocatalysts are prone to decomposition and surface structure transformation under the oxidizing OER potentials in the aggressive acidic environment, ultimately leading to a drastic decrease in catalytic performance.

A new study by the team from 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 studies on OER electrocatalysis by combining experiments and theoretical calculations.

Much attention has been paid to the OER mechanisms, which can be divided into two groups based on where oxygen atoms come from: the adsorbate evolution mechanism and the lattice oxygen oxidation mechanism.

There was a thorough discussion of how acidic OER electrocatalyst activity and stability relate. The scientists additionally proposed a stability testing strategy to assess the loss of intrinsic activity.

The use of carbon-based materials has been one of the unresolved concerns and current development challenges of the said acidic OER electrocatalysts. There were also some suggestions for synthesizing high-performance acidic OER electrocatalysts for PEM-based water electrolysis.

Magazine reference:

  1. Yichao Li, Yan Dong, Xuezhen Wang, Liang Chen. Electrocatalysts for oxygen evolution reaction in acidic media. Advanced materials. DOI: 10.1002/adma.202210565