Enhancing the Kinetics of Self-oscillating Chemical Reactions via Catalytic Ceria Nanomats

Chemical reactions that exhibit self-sustained oscillations show great promise for designing multifunctional materials for biomimetic applications. Belousov–Zhabotinsky (BZ) reactions are dynamical systems that operate far from equilibrium and thus serve as model systems for such applications. Catalyzed by a metal ion that undergoes rhythmic redox cycles, the solutions of BZ reactions exhibit periodic color change that corresponds to the oxidation state of the catalyst. Here, we demonstrate that by harnessing the interactions between nano- and continuum length scales, the oscillations in BZ reactions are significantly enhanced. In particular, we show that colloidal dispersions of ceria nanosheets (CeNSs) are excellent catalysts for BZ reactions, unlike nanoparticle-decorated graphene-based composites. Further, we identify the key steps of the reaction mechanism and determine the key kinetic parameters via combination of experiments and simulations. Specifically, we elucidate that the Oregonator model can be used to simulate BZ kinetics for CeNSs. We believe that through this maiden study, where bare non-graphene-based metal nanosheets have been used to catalyze oscillatory reactions, we open up new avenues to tune characteristics of dynamical systems for biomimetic applications.