Journal article
Creation of controllable cationic and anionic defects in tunnel manganese oxide nanowires for enhanced oxygen evolution reaction
Polyhedron, v 171
01 Oct 2019
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
The development of efficient oxygen evolution reaction (OER) catalysts is crucial to the environmental and economic feasibility of electrolysis for the production of hydrogen gas. In this work, two facile chemical treatments, acid leaching and transition metal doping, were shown to modify the chemical and structural properties of low cost and environmentally friendly alpha-MnO2 nanowire catalysts resulting in increased OER activity. Through a combination of XPS and XRD analyses, it was shown that a molten salt treatment of alpha-MnO2 nanowires with Co(NO3)(2) introduced Co2+ ions into the structural tunnels. The introduction of minimal amounts of cobalt (<6 at. %) more than doubled ultimate current densities achieved in linear sweep voltammetry tests. This result was attributed to a reduction of the average oxidation state of manganese in Co-doped samples and a decrease in Tafel slope below 80 mV.dec(-1). Acid leaching, on the other hand, is believed to modify nanowire topography through the creation of oxygen and manganese vacancies, exposing more active sites to participate in catalysis. A characterization approach combining atomic absorption spectroscopy and iodometric titration revealed a 5.1% increase in oxygen vacancies after 72 h of interaction with nitric acid. When these controllable defect formation approaches were applied in tandem, the high activity of the cobalt-doped samples was combined with the increased number of exposed active sites achieved through acid leaching producing a highly efficient electrocatalyst with more than a 3-fold increase in OER activity over pristine alpha-MnO2 nanowires. Our results establish that scalable and easy-to-implement approaches, such as acid leaching and transition metal doping, can lead to more than a three-fold increase in OER activity of low-cost non-toxic manganese oxides. This methodology can be beneficial for other material systems used as OER electrocatalysts. (C) 2019 Elsevier Ltd. All rights reserved.
Metrics
Details
- Title
- Creation of controllable cationic and anionic defects in tunnel manganese oxide nanowires for enhanced oxygen evolution reaction
- Creators
- Patrick J. West - Drexel UniversityBryan W. Byles - Drexel UniversityEkaterina Pomerantseva - Drexel University
- Publication Details
- Polyhedron, v 171
- Publisher
- Elsevier
- Number of pages
- 9
- Grant note
- CMMI-1635233 / National Science Foundation, USA; National Science Foundation (NSF)
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Materials Science and Engineering
- Web of Science ID
- WOS:000491625700004
- Scopus ID
- 2-s2.0-85069553387
- Other Identifier
- 991019169625204721
UN Sustainable Development Goals (SDGs)
This publication has contributed to the advancement of the following goals:
InCites Highlights
Data related to this publication, from InCites Benchmarking & Analytics tool:
- Web of Science research areas
- Chemistry, Inorganic & Nuclear
- Crystallography