Vapor–solid synthesis of monolithic single-crystalline CoP nanowire electrodes for efficient and robust water electrolysis
| Autor: | Lifeng Liu, Fang Xia, Junyuan Xu, Dehua Xiong, Xiuli Fu, Xuefei Gao, Sitaramanjaneya Mouli Thalluri, M. F. Cerqueira, Jian Liu, Wei Li, Weiguo Song |
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| Přispěvatelé: | Universidade do Minho |
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Phosphide
Nanotechnology 02 engineering and technology Overpotential 010402 general chemistry 7. Clean energy 01 natural sciences water electrolysis law.invention chemistry.chemical_compound law Engenharia dos Materiais [Engenharia e Tecnologia] Vapor–solid synthesis Tafel equation Electrolysis Science & Technology Electrolysis of water Alkaline water electrolysis Oxygen evolution General Chemistry 021001 nanoscience & nanotechnology 6. Clean water Nanowires electrodes 0104 chemical sciences Chemistry Chemical engineering chemistry Engenharia e Tecnologia::Engenharia dos Materiais Water splitting 0210 nano-technology CoP |
| Zdroj: | Chemical Science Chem. Sci. Repositório Científico de Acesso Aberto de Portugal Repositório Científico de Acesso Aberto de Portugal (RCAAP) instacron:RCAAP |
| Popis: | 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 () of merely 300 mV and a small Tafel slope of 78 mV dec1 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 = 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. L. F. Liu acknowledges the financial support of a FCT Investigator grant (No. IF/01595/2014) and exploratory grant (No. IF/ 01595/2014/CP1247/CT0001) awarded by the Portuguese Foundation of Science & Technology (FCT). W. Li and D. H. Xiong are thankful for the support of the Marie Skłodowska-Curie Action COFUND programme (NanoTrainforGrowth, grant No. 600375) for postdoctoral fellowships. This work was also partly financed by the European Commission Horizon 2020 project “CritCat” (Grant No. 686053). info:eu-repo/semantics/publishedVersion |
| Databáze: | OpenAIRE |
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