TY - JOUR
T1 - Nanocrystalline Ni5P4
T2 - A hydrogen evolution electrocatalyst of exceptional efficiency in both alkaline and acidic media
AU - Laursen, A. B.
AU - Patraju, K. R.
AU - Whitaker, M. J.
AU - Retuerto, M.
AU - Sarkar, T.
AU - Yao, N.
AU - Ramanujachary, K. V.
AU - Greenblatt, M.
AU - Dismukes, G. C.
N1 - Publisher Copyright:
© 2015 The Royal Society of Chemistry.
PY - 2015/3/1
Y1 - 2015/3/1
N2 - Producing hydrogen (H2) 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 H2. Renewable H2 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 Ni5P4 evolves H2 with geometric electrical to chemical conversion efficiency on par with Pt in strong acid (33 mV dec-1 Tafel slope and -62 mV overpotential at -100 mA cm-2 in 1 M H2SO4). The conductivity of Ni5P4 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-2, equivalent 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 H2 sources.
AB - Producing hydrogen (H2) 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 H2. Renewable H2 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 Ni5P4 evolves H2 with geometric electrical to chemical conversion efficiency on par with Pt in strong acid (33 mV dec-1 Tafel slope and -62 mV overpotential at -100 mA cm-2 in 1 M H2SO4). The conductivity of Ni5P4 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-2, equivalent 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 H2 sources.
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U2 - 10.1039/c4ee02940b
DO - 10.1039/c4ee02940b
M3 - Article
AN - SCOPUS:84924411666
VL - 8
SP - 1027
EP - 1034
JO - Energy and Environmental Science
JF - Energy and Environmental Science
SN - 1754-5692
IS - 3
ER -