Interactions of Different Janus Particles with Passive Tracers

In this manuscript we want to expand the strategies on tuneable phoretic interactions. Previously, we had kept the swimmer body fixed and varied fuel and light source. In this report we fix the fuel to hydrogen peroxide and change the species that favours its degradation, i.e. the 'catalytic' half on the Janus particles. Many materials are known to degrade hydrogen peroxide and our selection includes copper and silver, which present interesting effects besides the well known platinum.