Prussian blue analogue-derived Mn–Fe oxide nanocubes with controllable crystal structure and crystallinity as highly efficient OER electrocatalysts

Publication date: Available online 18 December 2019Source: Journal of Alloys and CompoundsAuthor(s): Quanyin Ma, Rui Dong, Heng Liu, Anquan Zhu, Lulu Qiao, Yongjin Ma, Juan Wang, Jianping Xie, Jun PanAbstractA series of ternary manganese iron oxides with different crystal structures, oxidation states and crystallinities were successfully fabricated by modulating the calcination conditions of Mn–Fe Prussian blue analogue (PBA) precursor (Mn3 [Fe(CN)6]2·nH2O). The obtained Mn–Fe oxides retained the nanocubic morphology of the PBA precursor, and a mesoporous structure was acquired as a result of gas molecule release during the pyrolysis process. Electrochemical oxygen evolution reaction (OER) activity of the as-prepared catalysts was tested, and among the bimetallic oxides, the catalyst that had a crystal structure similar to cubic bixbyite Mn1.2Fe0.8O3 (space group: Ia-3) with low crystallinity exhibited the most advanced OER activity. An overpotential of only 245 mV was required to achieve a current density of 10 mA cm−2, and the Tafel slope value was only 38 mV dec−1. The excellent OER activity is likely due to the hollow porous morphology of the samples, the synergistic effect of Mn and Fe, the defect-rich low crystallinity of the catalyst, and the cubic Mn1.2Fe0.8O3 structure (space group: Ia-3), which has an intrinsic activity superior to that of spinel Mn1.8Fe1.2O4.Graphical abstractMn-Fe PBA were used as precursor to obtain Mn-Fe ternary oxides with cont...
Source: Journal of Alloys and Compounds - Category: Chemistry Source Type: research