Nanostructured MnO2 has unique electrocatalytic properties towards the Oxygen Reduction Reaction (ORR, the main cathodic reaction in metal-air devices), representing an excellent alternative to the expensive platinum. Herein, we report the hydrothermal synthesis of bare and 5% Ti-doped α-MnO2 nanoparticles using two different oxidizing agents, namely ammonium persulfate for MH-N samples and potassium permanganate for MH-K ones. The physico-chemical characterizations show that oxidant cations induce different structural, morphological and surface properties of the final powders. Hence, correlations between the different α-MnO2 characteristics and their electrocatalytic performances towards the ORR are drawn, highlighting the diverse effect even on the kinetic point of view. The ORR activity in alkaline media is examined by means of Staircase - Linear Sweep Voltammetry (S-LSV), using Gas Diffusion Electrode (GDE) as the air-cathode. The presence of these nanoparticles in the GDEs leads to a significant shift of the ORR onset potential (∼100 mV) towards less cathodic values, underlining the electrocatalytic efficiency of all the nanopowders. Furthermore, high exchange current densities (j0) are determined for GDEs with Ti-doped MnO2, comparable to the well-performing Pd45Pt5Sn50, and making it a promising material for the ORR.

High-performance of bare and Ti-doped α-MnO2 nanoparticles in catalyzing the Oxygen Reduction Reaction / E. Pargoletti, G. Cappelletti, A. Minguzzi, S. Rondinini, M. Leoni, M. Marelli, A. Vertova. - In: JOURNAL OF POWER SOURCES. - ISSN 0378-7753. - 325(2016), pp. 116-128. [10.1016/j.jpowsour.2016.06.020]

High-performance of bare and Ti-doped α-MnO2 nanoparticles in catalyzing the Oxygen Reduction Reaction

E. Pargoletti;G. Cappelletti;A. Minguzzi;S. Rondinini;A. Vertova
2016

Abstract

Nanostructured MnO2 has unique electrocatalytic properties towards the Oxygen Reduction Reaction (ORR, the main cathodic reaction in metal-air devices), representing an excellent alternative to the expensive platinum. Herein, we report the hydrothermal synthesis of bare and 5% Ti-doped α-MnO2 nanoparticles using two different oxidizing agents, namely ammonium persulfate for MH-N samples and potassium permanganate for MH-K ones. The physico-chemical characterizations show that oxidant cations induce different structural, morphological and surface properties of the final powders. Hence, correlations between the different α-MnO2 characteristics and their electrocatalytic performances towards the ORR are drawn, highlighting the diverse effect even on the kinetic point of view. The ORR activity in alkaline media is examined by means of Staircase - Linear Sweep Voltammetry (S-LSV), using Gas Diffusion Electrode (GDE) as the air-cathode. The presence of these nanoparticles in the GDEs leads to a significant shift of the ORR onset potential (∼100 mV) towards less cathodic values, underlining the electrocatalytic efficiency of all the nanopowders. Furthermore, high exchange current densities (j0) are determined for GDEs with Ti-doped MnO2, comparable to the well-performing Pd45Pt5Sn50, and making it a promising material for the ORR.
Manganese dioxide; Hydrothermal synthesis; Oxidizing agents; Titanium doping; Metal-air devices; Oxygen Reduction Reaction (ORR)
Settore CHIM/02 - Chimica Fisica
New nanostructured materials for innovative lithium-air high-energy rechargeable batteries
JOURNAL OF POWER SOURCES
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/447877
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