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Crystalline Ni(OH) 2 /Amorphous NiMoO x Mixed‐Catalyst with Pt‐Like Performance for Hydrogen Production
Author(s) -
Dong Zihao,
Lin Fei,
Yao Yihang,
Jiao Lifang
Publication year - 2019
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.201902703
Subject(s) - amorphous solid , materials science , tafel equation , overpotential , hydrogen production , dissociation (chemistry) , electrolysis , catalysis , chemical engineering , alkaline water electrolysis , electrolysis of water , fourier transform infrared spectroscopy , hydrogen , inorganic chemistry , nickel , electrode , electrochemistry , chemistry , electrolyte , metallurgy , crystallography , organic chemistry , engineering
The achievement of effective alkaline hydrogen production from water electrolysis is an active field of research. Herein, an integrated electrode composed of crystalline Ni(OH) 2 and amorphous NiMoO x is fabricated onto nickel foam (denoted as Ni(OH) 2 –NiMoO x /NF). The hydrogen evolution reaction (HER) kinetics are optimized along with phase transformation process during soaking operation. An overpotential of 36 mV to drive 10 mA cm −2 along with the low Tafel slope of 38 mV dec −1 reveals the catalyst's excellent HER performance and a Heyrovsky‐step‐controlled HER mechanism. When assembled into a urea‐assisted water electrolyzer, a voltage of 1.42 V can reach 10 mA cm −2 . Further experiments and Fourier transform infrared spectroscopy (FTIR) results illustrate the synergy effect between crystalline and amorphous areas and the optimized water dissociation step. Crystalline Ni(OH) 2 serves as the scissor for water dissociation in an alkali environment to produce H*, while the amorphous NiMoO x layer serves as the location for H* adsorption and H 2 desorption.