Self-moving reaction droplets synergized by graphene-based nanocomposites

Chemo-mechanical transduction to perform locomotion is one of the characteristics of biological systems that has inspired the design of self-moving biomimetic systems. Here, we harness self-oscillating Belousov-Zhabotinsky (BZ) reaction, synergized by graphene-based catalytic mats to demonstrate spontaneous motion of the BZ reaction droplet in surrounding oil. Specifically, we synthesize graphene-based catalytic mats by decorating Ce and Ru nanoparticles (NP) on graphene nanosheets, thereby creating a 0D-2D heterostructures, and subsequently, use these mats to catalyze the BZ reaction. Our results demonstrate spontaneous locomotion of BZ droplets in oil bath due to the Marangoni flow that is brought about by the interaction between BZ reaction intermediates and surrounding oil. We further demonstrate that the velocity of the droplet motion is dependent upon the conductivity of the catalytic mats. In particular, we show two-fold increase in the droplet velocity when RuNP decorated graphene sheets are used to catalyze the BZ reaction instead of the traditional solution based BZ catalysts. Our findings can be used to design self-moving synthetic objects and opens up new avenues to control their behaviour through the use of 0D-2D hybrid nanomaterials.