Toward Reliable Assessment of Catalase-like Activity of Nanozymes: Current Assays, Critical Pitfalls, and the Quest for Standardization

Nanozymes are nanomaterials that exhibit enzyme-like catalytic activities and follow enzymatic reaction kinetics. As an important member of the nanozyme family, catalase nanozymes (CAT nanozyme) possess the catalase-like activity while standing out higher stability and lower cost compared to their natural counterparts. Accurately assessing the catalytic activity of CAT nanozymes is essential not only for guiding the design and development of novel CAT nanozymes but also for supporting their sustainable application and translational progress. To date, varieties of analytical methods—mainly adapted from protocols for natural catalase and industrial wastewater treatment practices—have been employed to assess the activity of CAT nanozymes. However, systematic and consensus-based approaches remain few. This article reviewed existing detection and evaluation techniques and compared their respective strengths and limitations, aiming to provide a theoretical and experimental foundation for the future establishment of standardized assessment methodologies.