Nanocrystalline Ni sub(5)P sub(4): a hydrogen evolution electrocatalyst of exceptional efficiency in both alkaline and acidic media
Producing hydrogen (H sub(2)) by splitting water with fossil-free electricity is considered a grand challenge for developing sustainable energy systems and a carbon dioxide free source of renewable H sub(2). Renewable H sub(2) may be produced from water by electrolysis with either low efficiency alk...
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Veröffentlicht in: | Energy & environmental science 2015-03, Vol.8 (3), p.1027-1034 |
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Sprache: | eng |
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Zusammenfassung: | Producing hydrogen (H sub(2)) by splitting water with fossil-free electricity is considered a grand challenge for developing sustainable energy systems and a carbon dioxide free source of renewable H sub(2). Renewable H sub(2) may be produced from water by electrolysis with either low efficiency alkaline electrolyzers that suffer 50-65% losses, or by more efficient acidic electrolyzers with rare platinum group metal catalysts (Pt). Consequently, research has focused on developing alternative, cheap, and robust catalysts made from earth-abundant elements. Here, we show that crystalline Ni sub(5)P sub(4) evolves H sub(2) with geometric electrical to chemical conversion efficiency on par with Pt in strong acid (33 mV dec super(-1) Tafel slope and -62 mV overpotential at -100 mA cm super(-2) in 1 M H sub(2)SO sub(4)). The conductivity of Ni sub(5)P sub(4) microparticles is sufficient to allow fabrication of electrodes without conducting binders by pressing pellets. Significantly, no catalyst degradation is seen in short term studies at current densities of -10 mA cm super(-2), equivalent to similar to 10% solar photoelectrical conversion efficiency. The realization of a noble metal-free catalyst performing on par with Pt in both strong acid and base offers a key step towards industrially relevant electrolyzers competing with conventional H sub(2) sources. |
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ISSN: | 1754-5692 1754-5706 |
DOI: | 10.1039/c4ee02940b |