Open AccessPreparation of Mesoporous/Microporous MnCo2O4 and Nanocubic MnCr2O4 Using a Single Step Solution Combustion Synthesis for Bifunction Oxygen Electrocatalysis
Author(s) -
Anchu Ashok,
Anand Kumar,
Janarthanan Ponraj,
Said Mansour
Publication year - 2020
Publication title -
journal of the electrochemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.258
H-Index - 271
eISSN - 1945-7111
pISSN - 0013-4651
DOI - 10.1149/1945-7111/ab679d
Subject(s) - electrocatalyst , oxygen , microporous material , materials science , tafel equation , crystallite , mesoporous material , chemical engineering , analytical chemistry (journal) , catalysis , chemistry , electrochemistry , metallurgy , electrode , composite material , biochemistry , organic chemistry , chromatography , engineering
We report the synthesis of mesoporous/microporous MnCo 2 O 4 and cubic MnCr 2 O 4 using solution combustion synthesis for oxygen reduction and oxygen evolution reactions. XRD and TEM analysis indicate small crystallites of MnCo 2 O 4 forming ultra-thin layer of irregular structures that lead to porous morphology. A slightly larger crystallite size was observed for MnCr 2 O 4 . The surface oxygen defect in MnCo 2 O 4 is much higher than MnCr 2 O 4 that enhances the active sites for the oxygen adsorption and promotes fast dissociation in presence of more exposed Mn/Co sites during the oxygen electrocatalysis. The electrochemical properties of the synthesized catalysts were analysed using CV, LSV, EIS and CA showing high limiting current density and kinetic current density, positive onset and halfwave potential and higher number of overall electron transfer in MnCo 2 O 4 that MnCr 2 O 4 . Chronoamperometric (CA) runs for 24 h shows excellent stability of MnCo 2 O 4 without any significant decrease in the current or potential value in ORR and OER. On basis of the activity and stability performance, MnCo 2 O 4 shows to be a promising bifunctional electrocatalyst, with significantly improved performance than previously reported Mn and Co mixed oxides, and comparable to Pt and Ru based catalysts in terms of durability, onset potential and Tafel slope.