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Porous Cobalt–Nickel Hydroxide Nanosheets with Active Cobalt Ions for Overall Water Splitting
Author(s) -
Wang Xiao,
Li Zhe,
Wu DeYao,
Shen GuRong,
Zou Chengqin,
Feng Yi,
Liu Hui,
Dong CunKu,
Du XiWen
Publication year - 2019
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201804832
Subject(s) - cobalt , nickel , materials science , hydroxide , porosity , cobalt hydroxide , cobalt extraction techniques , water splitting , ion , inorganic chemistry , chemical engineering , metallurgy , catalysis , chemistry , electrode , electrochemistry , composite material , organic chemistry , photocatalysis , engineering
Low‐cost and high‐performance catalysts are of great significance for electrochemical water splitting. Here, it is reported that a laser‐synthesized catalyst, porous Co 0.75 Ni 0.25 (OH) 2 nanosheets, is highly active for catalyzing overall water splitting. The porous nanosheets exhibit low overpotentials for hydrogen evolution reaction (95 mV@10 mA cm −2 ) and oxygen evolution reaction (235 mV@10 mA cm −2 ). As both anode and cathode catalysts, the porous nanosheets achieve a current density of 10 mA cm −2 at an external voltage of 1.56 V, which is much lower than that of commercial Ir/C‐Pt/C couple (1.62 V). Experimental and theoretical investigations reveal that numerous Co 3+ ions are generated on the pore wall of nanosheets, and the unique atomic structure around Co 3+ ions leads to appropriate electronic structure and adsorption energy of intermediates, thus accelerating hydrogen and oxygen evolution.