Journal
SMALL
Volume 14, Issue 22, Pages -Publisher
WILEY-V C H VERLAG GMBH
DOI: 10.1002/smll.201800421
Keywords
DFT calculations; hydrogen evolution reaction; in situ Raman; NiCoP; oxygen doping
Categories
Funding
- National Natural Science Foundation of China [51708543, 51438011, 51622204]
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An outstanding hydrogen evolution electrocatalyst should have a free energy of adsorbed atomic hydrogen of approximately zero, which enables not only a fast proton/electron-transfer step but also rapid hydrogen release. An economic and industrially viable alternative approach for the optimization of atomic hydrogen binding energy is urgently needed. Herein, guided by density functional theory (DFT) calculations, it is theoretically demonstrated that oxygen doping in NiCoP can indeed optimize the atomic hydrogen binding energy (e.g., |G(H*)| = 0.08, 0.12 eV on Co, P sites). To confirm this, NiCoP electrodes with controllable oxygen doping are designed and fabricated via alteration of the reducing atmosphere. Accordingly, an optimal oxygen-doped NiCoP (approximate to 0.98% oxygen) nanowire array is found to exhibit the remarkably low hydrogen evolution reaction (HER) overpotential of 44 mV to drive 10 mA cm(-2) and a small Tafel slope of 38.6 mV dec(-1), and long-term stability of 30 h in an alkaline medium. In neutral solution, only a 51 mV overpotential (@10 mA cm(-2)) is required, and the Tafel slope is 79.2 mV dec(-1). Meanwhile, in situ Raman spectra confirm the low formation overpotential (-30 mV) of NiCo-phosphate at the surface of approximate to 0.98% oxygen-doped NiCoP, which enables the material to show better HER performance.
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