Stable Magnetic Chemical Locomotive with Pd Nanoparticle Incorporated Ferromagnetic Oxide

Abstract

In this article, we present results on the development of a new magnetic chemical locomotive made of ferromagnetic cobalt ferrite (CoFe2O4), doped with Pd nanoparticles (NPs). The composite particles were found to be chemically stable in realizing magnetic chemical propulsion. Further, these particles strongly catalyzed the decomposition of hydrogen peroxide (H2O2) solution even when the strength of the solution was as low as 0.3%, making it efficient in inducing autonomous chemical locomotion. In addition, the velocity of the particles could be controlled by using dimethyl sulfoxide (DMSO), which is known to quench hydroxyl radicals in the solution. We also showed that these ferromagnetic structures possessed appreciable magnetization and were capable of being guided magnetically, while roving autonomously inside the liquid.

Poisoning of bubble propelled catalytic micromotors: the chemical environment matters

“…22 During the reaction, the hydroxyl radical ˙OH is the key to the formation of O 2 gas bubbles. 23 Based on the reaction mechanism, when the chemical quencher (DMSO in this case) is present, the rate of O 2 gas generation is given by: 23 where [S] stands for the active metal surface, k D , k 1S and k 2S represent the constants in the reaction processes and [DMSO] and [H 2 O 2 ] are the concentrations of DMSO and hydrogen peroxide in the solution, respectively. From the above equation, the generation of oxygen gas depends on three factors: the concentration of hydrogen peroxide, the amount of DMSO (or other molecules that are able to quench the radical reaction) as well as the active surface area of the catalyst metal, Pt.…”

Manipulation of micro- and nanostructure motion with magnetic fields

“…Similar experiments were also performed with cobalt ferrite microparticles, which were doped with palladium. 44 In a solution of hydrogen peroxide, propulsion of the particles was determined by oxygen formation on the particle surface. The authors demonstrated that small magnetic elds could be used to align and hence steer the ferromagnetic particles.…”

Active Steerable Catalytic Supraparticles Shuttling on Preprogrammed Vertical Trajectories

“…In addition, it is also possible to collect and entrap the particles with a sufficiently strong magnetic field. It might be noted that magnetic control of the trajectory of particles has for instance also been reported for the case of 150 μm sized Pd‐CoFe 2 O 4 particles that decompose H 2 O 2 and move on the liquid surface or hollow microparticles made of MnFe 2 O 4 …”