Nanostructured Manganese Oxide Supported on Carbon Nanotubes for Electrocatalytic Water Splitting

Katharina Mette, Arno Bergmann, Jean-Philippe Tessonnier*, Michael Haevecker, Lide Yao, Thorsten Ressler, Robert Schloegl, Peter Strasser, Malte Behrens

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Incipient wetness impregnation and a novel deposition symproportionation precipitation were used for the preparation of MnOx/CNT electrocatalysts for efficient water splitting. Nanostructured manganese oxides have been dispersed on commercial carbon nanotubes as a result of both preparation methods. A strong influence of the preparation history on the electrocatalytic performance was observed. The as-prepared state of a 6.5 wt.?% MnOx/CNT sample could be comprehensively characterized by comparison to an unsupported MnOx reference sample. Various characterization techniques revealed distinct differences in the oxidation state of the Mn centers in the as-prepared samples as a result of the two different preparation methods. As expected, the oxidation state is higher and near +4 for the symproportionated MnOx compared to the impregnated sample, where +2 was found. In both cases an easy adjustability of the oxidation state of Mn by post-treatment of the catalysts was observed as a function of oxygen partial pressure and temperature. Similar adjustments of the oxidation state are also expected to happen under water splitting conditions. In particular, the 5 wt.?% MnO/CNT sample obtained by conventional impregnation was identified as a promising catalytic anode material for water electrolysis at neutral pH showing high activity and stability. Importantly, this catalytic material is comparable to state-of-art MnOx catalyst operating in strongly alkaline solutions and, therefore, offers advantages for hydrogen production from waste and sea water under neutral, hence, environmentally benign conditions.

Original languageEnglish
Pages (from-to)851-862
Number of pages12
JournalChemCatChem
Volume4
Issue number6
DOIs
Publication statusPublished - Jun 2012
MoE publication typeA1 Journal article-refereed

Keywords

  • carbon nanotubes
  • catalyst preparation
  • electrocatalysis
  • manganese oxide
  • oxygen evolution reaction
  • X-RAY-ABSORPTION
  • OXYGEN REDUCTION
  • CATALYSTS
  • SPECTROSCOPY
  • ELECTRODES
  • OXIDATION
  • BEHAVIOR
  • CU
  • NANOPARTICLES
  • ELECTROLYSIS

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