Journal article
Vapor–solid synthesis of monolithic single-crystalline CoP nanowire electrodes for efficient and robust water electrolysis
Chemical Science, Vol.8(4), pp.2952-2958
2017
Abstract
Electrochemical water splitting into hydrogen and oxygen is a promising technology for sustainable energy storage. The development of earth-abundant transition metal phosphides (TMPs) to catalyze the hydrogen evolution reaction (HER) and TMP-derived oxy-hydroxides to catalyze the oxygen evolution reaction (OER) has recently drawn considerable attention. However, most monolithically integrated metal phosphide electrodes are prepared by laborious multi-step methods and their operational stability at high current densities has been rarely studied. Herein, we report a novel vapor–solid synthesis of single-crystalline cobalt phosphide nanowires (CoP NWs) on a porous Co foam and demonstrate their use in overall water splitting. The CoP NWs grown on the entire surface of the porous Co foam ligaments have a large aspect ratio, and hence are able to provide a large catalytically accessible surface over a given geometrical area. Comprehensive investigation shows that under the OER conditions CoP NWs are progressively and conformally converted to CoOOH through electrochemical in situ oxidation/dephosphorization; the latter serving as an active species to catalyze the OER. The in situ oxidized electrode shows exceptional electrocatalytic performance for the OER in 1.0 M KOH, delivering 100 mA cm−2 at an overpotential (η) of merely 300 mV and a small Tafel slope of 78 mV dec−1 as well as excellent stability at various current densities. Meanwhile, the CoP NW electrode exhibits superior catalytic activity for the HER in the same electrolyte, affording −100 mA cm−2 at η = 244 mV and showing outstanding stability. An alkaline electrolyzer composed of two symmetrical CoP NW electrodes can deliver 10 and 100 mA cm−2 at low cell voltages of 1.56 and 1.78 V, respectively. The CoP NW electrolyzer demonstrates exceptional long-term stability for overall water splitting, capable of working at 20 and 100 mA cm−2 for 1000 h without obvious degradation.
Details
- Title
- Vapor–solid synthesis of monolithic single-crystalline CoP nanowire electrodes for efficient and robust water electrolysis
- Authors/Creators
- W. Li (Author/Creator) - International Iberian Nanotechnology LaboratoryX. Gao (Author/Creator) - Beijing National Laboratory for Molecular SciencesD. Xiong (Author/Creator) - International Iberian Nanotechnology LaboratoryF. Xia (Author/Creator) - Murdoch UniversityJ. Liu (Author/Creator) - Beijing National Laboratory for Molecular SciencesW-G Song (Author/Creator) - Beijing National Laboratory for Molecular SciencesJ. Xu (Author/Creator) - International Iberian Nanotechnology LaboratoryS.M. Thalluri (Author/Creator) - International Iberian Nanotechnology LaboratoryM.F. Cerqueira (Author/Creator) - University of MinhoX. Fu (Author/Creator) - Beijing University of Posts and TelecommunicationsL. Liu (Author/Creator) - International Iberian Nanotechnology Laboratory
- Publication Details
- Chemical Science, Vol.8(4), pp.2952-2958
- Publisher
- Royal Society of Chemistry
- Identifiers
- 991005543361307891
- Copyright
- © 2017 Royal Society of Chemistry
- Murdoch Affiliation
- Murdoch University
- Language
- English
- Resource Type
- Journal article
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- Collaboration types
- Domestic collaboration
- International collaboration
- Citation topics
- 2 Chemistry
- 2.62 Electrochemistry
- 2.62.76 Electrocatalysis
- Web Of Science research areas
- Chemistry, Multidisciplinary
- ESI research areas
- Chemistry