Abstract
The electrocatalytic oxygen reduction process (ORR) is one of the possible methods for producing sustainable energy, but its slow kinetics necessitates the use of inexpensive and efficient catalysts. Herein, Fe3O4 nanoparticles (Fe3O4 NPs) were loaded onto multiwall carbon nanotubes (Fe3O4@CNTs) using a single-step microwave-assisted strategy. The prepared Fe3O4@CNTs composite was characterized via multiple analytical techniques, and the results suggested a thin film of Fe3O4 NPs coating on the CNT surface, having a high specific surface area and pore volume. The prepared Fe3O4@CNTs composite exhibited a positive shift in ORR half-wave potential of 240 and 20 mV with respect to Fe3O4 and 20% Pt/C catalysts, respectively. The improved ORR activity of the Fe3O4@CNTs composite can be attributed to the synergetic interaction between CNTs and Fe3O4, which is also supported by theoretical simulations. Furthermore, the Fe3O4@CNTs composite showed superior cycling stability and remarkable methanol tolerance, proving its applicability as an ORR catalyst at a practical level. This research will aid in the development of microwave-based strategies for producing efficient ORR catalysts. It will also give a basic understanding of the relationships between composition, structure, and activity.
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•A microwave-based approach was adopted to prepare Fe3O4@CNTs nanocomposite.•The structural and surface features of Fe3O4@CNTs composite was fully characterized.•Fe3O4@CNTs composite showed better ORR activity, durability and methanol tolerance.•DFT calculations were used to explain Fe3O4@CNTs' enhanced ORR activity.