I think that the best methods for assessment Catalase activity are:
1. Hadwan MH, kadhum Ali S. New spectrophotometric assay for assessments of catalase activity in biological samples. Analytical biochemistry. 2018 Feb 1;542:29-33.
https://www.ncbi.nlm.nih.gov/pubmed/29175424
2. Hadwan MH. Simple spectrophotometric assay for measuring catalase activity in biological tissues. BMC biochemistry. 2018 Dec;19(1):7.