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Scalable Synthesis of Efficient Water Oxidation Catalysts: Insights into the Activity of Flame‐Made Manganese Oxide Nanocrystals
Author(s) -
Liu Guanyu,
Hall Jeremy,
Nasiri Noushin,
Gengenbach Thomas,
Spiccia Leone,
Cheah Mun Hon,
Tricoli Antonio
Publication year - 2015
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201500704
Subject(s) - catalysis , calcination , electrochemistry , x ray photoelectron spectroscopy , chemical engineering , manganese , oxide , materials science , electrolyte , nanoparticle , nanocrystal , inorganic chemistry , fourier transform infrared spectroscopy , nanotechnology , chemistry , electrode , organic chemistry , metallurgy , engineering
Abstract Chemical energy storage by water splitting is a promising solution for the utilization of renewable energy in numerous currently impracticable needs, such as transportation and high temperature processing. Here, the synthesis of efficient ultra‐fine Mn 3 O 4 water oxidation catalysts with tunable specific surface area is demonstrated by a scalable one‐step flame‐synthesis process. The water oxidation performance of these flame‐made structures is compared with pure Mn 2 O 3 and Mn 5 O 8 , obtained by post‐calcination of as‐prepared Mn 3 O 4 (115 m 2 g −1 ), and commercial iso‐structural polymorphs, probing the effect of the manganese oxidation state and synthetic route. The structural properties of the manganese oxide nanoparticles were investigated by XRD, FTIR, high‐resolution TEM, and XPS. It is found that these flame‐made nanostructures have substantially higher activity, reaching up to 350 % higher surface‐specific turnover frequency (0.07 μmolO2 m −2 s −1 ) than commercial nanocrystals (0.02 μmolO2 m −2 s −1 ), and production of up to 0.33 mmolO2 mol Mn −1 s −1 . Electrochemical characterization confirmed the high water oxidation activity of these catalysts with an initial current density of 10 mA cm −2 achieved with overpotentials between 0.35 and 0.50 V in 1 m NaOH electrolyte.