Figure 3.

(a) Photocatalytic reaction occurs on TiO₂/Pt to produce a chemical gradient drive mode. The figure has been reproduced with permission from the Royal Society of Chemistry [123]. (b) This is the bubble propulsion mechanism of the Am-TiO₂/Au Janus MNM (micro/nanomotor) in the solution containing 15 wt% H₂O₂ and 5 wt% Triton-x100. The figure has been reproduced with permission from The Royal Society of Chemistry [135]. (c) This is a schematic of azobenzene coated polymer nanoparticles driven by light-induced surface tension in an aqueous medium. The figure has been reproduced with permission from the American Chemical Society [136].