Electrocatalytic activity and structural transformation of Ca2Sr2Mn2MO10-δ (M = Fe, Co)

• Published in: Ionics 2022, Vol.28 (1), p.397-406
• Main Authors: Karki, Surendra B., Hona, Ram Krishna, Ramezanipour, Farshid
• Format: Article
• Language: English
• Subjects: Chemistry; Chemistry and Materials Science; Condensed Matter Physics; Electrochemistry; Energy Storage; Hydrogen evolution reactions; Manganese; Optical and Electronic Materials; Original Paper; Renewable and Green Energy; Stacks; Water splitting
• ISSN: 0947-7047; 1862-0760
• DOI: 10.1007/s11581-021-04313-5

The structural transformation between Ca 2 Sr 2 Mn 2 FeO 10-δ and Ca 2 Sr 2 Mn 2 CoO 10-δ and the enhancement in electrocatalytic activity is reported. Ca 2 Sr 2 Mn 2 FeO 10-δ has a structure where corner-sharing (Mn/Fe)O 6 octahedra form triple-layered stacks and Ca/Sr are located in spaces within and between the stacks. The incorporation of cobalt results in Ca 2 Sr 2 Mn 2 CoO 10-δ , which has a greater concentration of oxygen vacancies and a quasi-one-dimensional structure, consisting of chains of CoO 6 –MnO 6 –MnO 6 –CoO 6 polyhedra with distorted trigonal prismatic and octahedral geometry. Detailed investigation of the electrocatalytic activities of these materials indicates that these compounds are able to catalyze both half reactions of water splitting, namely, hydrogen-evolution reaction (HER) and oxygen-evolution reaction (OER). Ca 2 Sr 2 Mn 2 CoO 10-δ shows enhanced electrocatalytic properties compared with Ca 2 Sr 2 Mn 2 FeO 10-δ . The former material exhibits lower overpotential and greater electrochemically active surface area, as well as faster kinetics for both HER and OER processes. Graphical abstract