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Active Edge Sites Engineering in Nickel Cobalt Selenide Solid Solutions for Highly Efficient Hydrogen Evolution
Author(s) -
Xia Chuan,
Liang Hanfeng,
Zhu Jiajie,
Schwingenschlögl Udo,
Alshareef Husam N.
Publication year - 2017
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201602089
Subject(s) - overpotential , tafel equation , exchange current density , materials science , cobalt , nickel , electrolyte , ternary operation , hydrogen , water splitting , solid solution , chemical engineering , inorganic chemistry , selenide , hydrogen production , chemistry , electrode , catalysis , electrochemistry , metallurgy , biochemistry , organic chemistry , photocatalysis , selenium , computer science , engineering , programming language
An effective multifaceted strategy is demonstrated to increase active edge site concentration in Ni 0.33 Co 0.67 Se 2 solid solutions prepared by in situ selenization process of nickel cobalt precursor. The simultaneous control of surface, phase, and morphology result in as‐prepared ternary solid solution with extremely high electrochemically active surface area ( C dl = 197 mF cm −2 ), suggesting significant exposure of active sites in this ternary compound. Coupled with metallic‐like electrical conductivity and lower free energy for atomic hydrogen adsorption in Ni 0.33 Co 0.67 Se 2 , identified by temperature‐dependent conductivities and density functional theory calculations, the authors have achieved unprecedented fast hydrogen evolution kinetics, approaching that of Pt. Specifically, the Ni 0.33 Co 0.67 Se 2 solid solutions show a low overpotential of 65 mV at −10 mV cm −2 , with onset potential of mere 18 mV, an impressive small Tafel slope of 35 mV dec −1 , and a large exchange current density of 184 µA cm −2 in acidic electrolyte. Further, it is shown that the as‐prepared Ni 0.33 Co 0.67 Se 2 solid solution not only works very well in acidic electrolyte but also delivers exceptional hydrogen evolution reaction (HER) performance in alkaline media. The outstanding HER performance makes this solid solution a promising candidate for mass hydrogen production.