Work

Overlooked Impact of Electrolyte Purity on Benchmarking Cathodes in Alkaline Water Electrolysis

Year: 2026

Type: article

Abstract: A catalyst’s performance is inherently linked to its operating environment. Therefore, evaluation under appropriate experimental conditions is essential for accurate results. This work underscores the impact of electrolyte purity on the performance of nickel-based catalysts in alkaline water electrolysis, a factor well recognized in oxygen evolution research but often neglected in hydrogen evolution studies. We show that trace impurities in laboratory-grade KOH can significantly distort the apparent performance of nickel cathodes during hydrogen evolution at industrially relevant conditions (1000 mA/cm 2 in 6 M KOH). These effects persist even when no visible deposits are present. Fundamental studies of nickel-based catalysts should use only high-purity-grade KOH. However, for industrial settings where impurities are likely unavoidable, testing conditions should be adjusted accordingly to ensure meaningful results.

Source: ACS electrochemistry.

DOI: 10.1021/acselectrochem.5c00326

Authors: Ragne Pärnamäe, Michele Tedesco, Philipp Kuntke, Hubertus V. M. Hamelers

Institutions: Wetsus, European Centre of Excellence for Sustainable Water Technology, Wageningen University & Research

Language: English

Topic: Electrocatalysts for Energy Conversion

Subfield: Renewable Energy, Sustainability and the Environment

Field: Energy

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: green

Funders: European Commission, Ministry of Infrastructure and Water Management, HORIZON EUROPE Framework Programme, Interreg