Template-free synthesis of mesoporous manganese oxides with catalytic activity in the oxygen evolution reaction. Issue 4 (20th April 2017)

• Record Type: Journal Article
• Authors: Lian, Suoyuan; Browne, Michelle P.; Domínguez, Carlota; Stamatin, Serban N.; Nolan, Hugo; Duesberg, Georg S.; Lyons, Michael E. G.; Fonda, Emiliano; Colavita, Paula E.
• Is Part Of: Sustainable energy & fuels. Volume 1:Issue 4(2017)
• Page Start: 780
• Page End: 788
• Publication Date: 2017-04-20
• Subjects: Renewable energy sources -- Periodicals; Fuel cells -- Periodicals; Electric batteries -- Periodicals; Electrochemistry -- Periodicals; 660.297
• DOI: 10.1039/c7se00086c
• Languages: English
• ISSNs: 2398-4902

Abstract

Abstract : Solvothermally synthesised MnCO3 leads to template-free formation of highly porous, defect-rich MnO2 with high activity in water oxidation. Abstract : Porous manganese carbonate was obtained via solvothermal synthesis using ethanol and urea. The manganese carbonate was subsequently used as a precursor to synthesise mesoporous manganese oxides via thermal treatments at three various temperatures. X-ray diffraction and Extended X-ray Absorption Fine Structure (EXAFS) results shows that γ-MnO2 is synthesised at 380 and 450 °C while Mn2 O3 is produced at the annealing temperature of 575 °C. X-ray absorption spectra show that γ-MnO2 converts completely to Mn2 O3 after annealing over the 450–575 °C range. The oxides obtained at 380 °C and 450 °C possess extremely high specific surface area, which is of interest for catalytic applications. The oxides were investigated as electrocatalysts for the oxygen evolution reaction; the oxide prepared at the lowest annealing temperature was found to be the optimum catalyst with an overpotential of 427 ± 10 mV at a current density of 10 mA cm −2, normalised by the geometric area. The improved catalytic activity was related to the presence of defect-rich and highly porous manganese dioxide at the lowest annealing temperature.