Bimetallic and multimetallic nanoparticles as nanozymes

Nanozymes are defined as nanomaterials, which possess the intrinsic enzyme-like activities. They were introduced as a response to the needs for stable, inexpensive and universal enzyme mimetics which could be used, among others, for analytics, diagnostics and biomedicine. As they typically exhibit at least one oxidoreductase-like activity, they can replace these catalysts in many applications typical for such enzymes. Moreover, due to the fact, that besides interesting chemical properties, they are very often also characterized with the unique physical and optical properties the potential of their application is not fully discovered, however more and more interesting concepts concerning their use have been shown for last few years. The combination of two or more metals in a nanozyme structure allows to take advantage of properties of all constituents and often new fascinating properties appear as a result of synergetic effect. It prompted us to delve into this topic and comment some fundamental phenomena and new discoveries concerning bimetallic and multimetallic nanozymes. Due to the fact, that thorough understanding of rational regulation and manipulation of the activities of nanozymes through alloying or doping and proper choice of conditions, under which they are used, are of great significance, the focus was paid to these issues. Additionally, the most interesting applications of such nanozymes were demonstrated in the framework of this review.