Carbon monoxide (CO) is an odorless gas which is extremely hazardous for health and the environment. It is usually produced as a result of the incomplete combustion of hydrocarbon compounds. Thus the catalytic oxidation of CO has become a crucial step for the control of CO emissions in a wide range of processes, such as vehicle exhaust treatment and purification of hydrogen for fuel cell applications. Moreover, due to its simplicity, CO oxidation is used as a probe reaction to model more complex reactions such as the Fischer-Tropsch synthesis. Platinum group metals (PGMs) including Pt, Pd, Rh, etc. are widely known for their excellent catalytic activity for many reactions of critical importance such as CO oxidation. Catalyst nanoparticles (NPs) are usually stabilized by dispersion over metal-oxide supports in industrial applications. CO oxidation usually displays bistable kinetics over Pt. At low temperature and/or low O 2 pressure, it suffers from CO self-poisoning (chemical deactivation), slowing down the reaction rate. The catalyst surface is then saturated with a CO layer that prevents the coadsorption of O 2 . Therefore, there are not enough free active sites in which the O 2 molecules can impinge and react with the coadsorbed CO, and the catalyst is rendered totally inactive after solely a few number of catalytic cycles, costing billions of dollars annually in the industry. At high temperature and/or high O 2 pressure on the other hand, a first order kinetic phase transition (i.e., alteration of the adsorbates adsorption-desorption equilibrium) occurs leading to a more reactive state. Now, the adsorbed CO reacts immediately increasing the CO 2 formation rate and dissociated O becomes the predominant species. Since high temperature favors catalyst deactivation due to sintering and coking, CO poisoning imposes severe constraints over the maneuverability of the optimal operating reaction conditions. This scenario together with the high cost and limited availability of Pt hampers its use in large-scale production.