Removal of carboxylated polystyrene bead (PS-COOH) by individual Au@Ni@TiO2 micromotors 3 µm carboxylic polystyrene particles were synthesized by dispersion polymerization. In brief, 1.35 g of PVP was dissolved in 102 mL of ethanol and 10 mL of water in a 250 mL roundbottom flask under N2 gas flux with stirring at 280 rpm. Then 0.3 g of acrylic acid was added. The mixed solution containing 0.3 g of AIBN and 15 g of styrene was added to the previous solution.