In situ facile loading of noble metal nanoparticles on polydopamine nanospheres via galvanic replacement reaction for multifunctional catalysis

Noble metal nanoparticles (Pd, Ag, Pt, Au) with small and relatively uniform sizes were loaded on polydopamine nanospheres through in situ galvanic replacement reaction in aqueous solution. No additional reductant, surfactant or organic solvent was needed. X-ray photoelectron spectroscopy results revealed that the amount of quinone increased, while the amount of phenolic hydroxyl decreased on PDA nanospheres, indicating that the galvanic displacement reaction occurred between catechol groups and noble metal ions. The as-prepared PDA/Pd exhibited high catalytic activity and excellent stability in styrene hydrogenation. Moreover, PDA spheres retains the photo-thermal effect to serve as a nano-sized heater to accelerate the catalytic reactions under near-infrared illumination.