The stability of seawater electrolysis was increased by scientists by clarifying the corrosion mechanism of the corrosive anion Br- on Ni-based anodes. The study was published in the journal Nature Communications.
Hydrogen production through the electrolysis of salt water is seen as a viable and affordable energy storage and conversion strategy that helps achieve “highest carbon dioxide emissions and carbon neutrality.” However, the use of brine electrolysis for hydrogen production has been restricted due to poor anode durability.
The researchers examined the mechanism of anode corrosion in seawater electrolysis based on previous work on the stability of seawater electrolysis. In seawater electrolysis, Br- in addition to Cl- has been found to be more damaging to Ni-based anodes.
Evaluation results of electrochemical experiments showed that Ni-based anodes in Br-containing electrolytes have lower corrosion resistance and faster corrosion kinetics than those in Cl-containing electrolytes.
According to in situ electrochemical studies, in Ni substrates, Cl- likes to produce localized corrosion with narrow, deep pits, while Br- tends to produce extensive corrosion with wide, shallow pits.
According to studies using density functional theory and poked elastic band simulations, the slower diffusion and lower reaction energy of Br- compared to Cl- in the passivation layer are responsible for this difference in corrosion behavior.
Additionally, in Ni-based electrodes with catalysts such as Br-, NiFe-LDH, electrolysis can cause the catalyst layer to exfoliate over a large area, resulting in a rapid decrease in performance.
Although Br- is present in minimal amounts (0,53 mM) in salt water, it has a significant impact on the corrosion behavior of Ni substrates and consequently requires additional evaluation.
This study's investigation of Br- and Cl- corrosion mechanisms on Ni-based anodes may aid in the design and synthesis of long-lasting and reliable saltwater electrolysis anodes.
Source: phys.org/news
📩 10/09/2023 23:57