Enhancing the Self-Propelled Motion of Hydrogen Peroxide Fueled Active Particles with Formic Acid and Other Oxygen Scavengers

We report enhanced active particle motion in hydrogen peroxide-fueled self-diffusiophoretic active particle systems of up to 400% via addition of low concentrations of oxygen scavenging agents such as formic acid (as well as other organic acids, hydrazine, and citric acid), whereas active motion was inhibited at higher concentrations. Control experiments showed that enhanced motion was decoupled from catalytic hydrogen peroxide decomposition rate and insensitive to particle surface chemistry. Experimental results point to bulk oxygen scavenging as the cause for the enhanced active motion, representing a realization of recently predicted promotional effects of product sinks on self-diffusiophoretic motion. Diminished active motion at high oxygen scavenger concentrations was attributed to catalytic site blocking by adsorbed solute.