Eco-friendly seeded FeO-Ag nanocrystals: a new type of highly efficient and low cost catalyst for methylene blue reduction.

Hybrid FeO-Ag nanocrystals, a new type of highly efficient and reusable catalyst for methylene blue (MB) reduction, are fabricated by a novel seed deposition process. X-ray diffraction and Mössbauer spectroscopy results show that the developed iron oxides are in a pure magnetite FeO phase. Upon manipulating the amount of Ag seeds capsuled on the modified surfaces of FeO nanocrystals, the catalytic capacities on the reduction of MB can be precisely adjusted with a tunable fabrication cost control. The linear correlation of the reduced MB concentration reaction time catalyzed by our developed hybrid FeO-Ag nanocrystals is coherent with pseudo first order kinetics. Importantly, with remarkable recyclability features, the hybrid FeO-Ag nanocrystals can be easily separated by applying an external magnetic field. The tailored catalytic performances of the hybrid FeO-Ag nanocrystals during MB reduction are attributed to the optimized dynamic electron transfer process, which dominates the electrochemical mechanism wherein the nucleophilic BH ions donate electrons to electrophilic organic MB through Ag seeds in a regulated amount. Such developed hybrid FeO-Ag nanocrystals pave the way towards the mass production of highly efficient and low cost catalysts for methylene blue reduction.