Journal Pre-proof A Review on Metal Nanozyme-Based Sensing of Heavy Metal Ions: Challenges and Future Perspectives Binesh Unnikrishnan, Chia-Wen Lien, Han-Wei Chu, Chih-Ching Huang PII: S0304-3894(20)31386-8 DOI: https://doi.org/10.1016/j.jhazmat.2020.123397 Reference: HAZMAT 123397 To appear in: Journal of Hazardous Materials Received Date: 28 April 2020 Revised Date: 30 June 2020 Accepted Date: 2 July 2020 Please cite this article as: Unnikrishnan B, Lien C-Wen, Chu H-Wei, Huang C-Ching, A Review on Metal Nanozyme-Based Sensing of Heavy Metal Ions: Challenges and Future Perspectives, Journal of Hazardous Materials (2020), doi: https://doi.org/10.1016/j.jhazmat.2020.123397 This is a PDF ﬁle of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the deﬁnitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its ﬁnal form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2020 Published by Elsevier.