Tuning of eg electron occupancy of MnCo2O4 spinel for oxygen evolution reaction by partial substitution of Co by Fe at octahedral sites

Enhanced Electrochemical Performance of MnCo1.5Fe0.5O4Spinel for Oxygen Evolution Reaction through Heat Treatment

“…MnCo 1.5 Fe 0.5 O 4 spinel oxide powders were prepared using the EDTA-citric acid method described in detail in previous work . The obtained powders were heat-treated at various temperatures (400, 600, 800, and 1000 °C) for 2 h in air on alumina trays.…”

“…MnCo 1.5 Fe 0.5 O 4 spinel oxide powders were prepared using the EDTA-citric acid method described in detail in previous work. 14 The obtained powders were heat-treated at various temperatures (400, 600, 800, and 1000 °C) for 2 h in air on alumina trays. Using yttria-stabilized zirconia (YSZ, Inframat) spherical grinding media (1 mm), the calcined powders were ball-milled in ethanol for 144 h in 20 mm diameter glass vials with a rotation speed of 100 rpm to improve the electrocatalytic performance.…”

“…Recently, we have further improved the OER activity of MnCo 2 O 4 by partially substituting Co with Fe. 14 When compared to pristine MnCo 2 O 4 , an ideal amount of Fe incorporated into the octahedral sites (MnCo 1.5 Fe 0.5 O 4 ) improved the overpotential of the OER by 30 mV (at a benchmark 10 mA cm –2 GEO current density). A volcano-type shape function of the e g occupancy at octahedra sites and the OER-specific activity was observed.…”

“…The authors concluded that the enhanced electrocatalytic activity was primarily attributed to improved electronic communication through Co 3+ /Co 2+ and Ni 3+ /Ni 2+ redox couples, and a high ECSA providing ample accessible active sites. Recently, we have further improved the OER activity of MnCo 2 O 4 by partially substituting Co with Fe . When compared to pristine MnCo 2 O 4 , an ideal amount of Fe incorporated into the octahedral sites (MnCo 1.5 Fe 0.5 O 4 ) improved the overpotential of the OER by 30 mV (at a benchmark 10 mA cm –2 GEO current density).…”

Self-Supported CoSe2 Nanorods for Efficient Oxygen Evolution and Urea Oxidation

“…It has been reported that when the activated atoms in the octahedral coordination have too low e g orbital occupancy (e g < 1), the binding with oxygen will enhance, while the binding with oxygen will weaken when the activated atoms have too high e g orbital occupancy (e g > 1). Therefore, when the e g orbital of the transition metal surface ion is filled to 1, the catalyst exhibits the optimal OER activity. − Cubic CoSe 2 is a good choice because its electron configuration is close to the ideal e g filling. , …”