As shown in the scheme of photocatalytic propulsion of micromotor in water (Figure ), under UV illumination, photo-excitation process takes place within TiO2, creating conduction band electrons and valence band holes. Holes involve in the oxidation reaction of water at TiO2 hemisphere, which produces protons. Electrons are transferred to metal cap and involve the reduction of protons at metal cap hemisphere. The consumption of protons leads to a fluid flow toward the metal cap, thus contributing the photocatalytic propulsion of Au@Ni@TiO2 micromotors. Similar to the case in water, the catalytic decomposition of H2O2 via oxidationreaction mechanism occur on the micromotors in H2O2 solution (Figure ), propelling the micromotors. It can actively self-propel with the speed of 14.72 µm s -1 in H2O and 65.52 µm s -1 in 0.1% H2O2 solution with UV light, as shown in the Figure , B (Video S1, S2). The motion tracklines for micromotors during 2 s are displayed. Just as noted earlier with Au@TiO2 micromotors, the micromotors achieve faster speeds in H2O2 compared to H2O, but steady motion in both fuels.