Crystalline Multi-Metal
Nanosheets Array with Enriched
Oxygen Vacancies as Efficient and Stable Bifunctional Electrocatalysts
for Water Splitting
Muhammad
Imran Abdullah
Asima Hameed
Tuoping Hu
Ning Zhang
Mingming Ma
10.1021/acsaem.9b01944.s001
https://acs.figshare.com/articles/journal_contribution/Crystalline_Multi-Metal_Nanosheets_Array_with_Enriched_Oxygen_Vacancies_as_Efficient_and_Stable_Bifunctional_Electrocatalysts_for_Water_Splitting/10354613
The electrolysis of water on a large scale for hydrogen
production
needs low cost, efficient, and stable electrocatalysts for the hydrogen
evolution reaction (HER) and oxygen evolution reaction (OER). Herein,
we report the synthesis of a crystalline multimetal (Co, Ni, Fe) nanosheets
array (NSA) enriched with oxygen vacancies by a simple electrosynthesis
method, which can serve as efficient and stable electrocatalysts for
both OER and HER. The oxygen vacancies are generated by electro-oxidation
or electro-reduction of CoFeNiSe precursor via the replacement of
selenium by oxygen. For HER, as synthesized CoFeNi-NSA achieved a
400 mA cm<sup>–2</sup> current density at a low overpotential
of −211 mV. For OER, CoFeNi-NSA was in situ oxidized to form
CoFeNiO-NSA, which achieved a 400 mA cm<sup>–2</sup> current
density at a low overpotential of 270 mV. The activities of CoFeNi-NSA
and CoFeNiO-NSA remained stable after 150 h HER or OER test at high
current densities, showing higher activity and stability than noble-metal
electrocatalysts Pt/C and IrO<sub>2</sub>, respectively. The electrolytic
cell of CoFeNiO-NSA∥CoFeNi-NSA can achieve a high current density
of 400 mA cm<sup>–2</sup> at a moderate voltage of 1.98 V.
During a long-term water splitting test, the voltage of the electrolytic
cell remained stable at 1.76 V for 150 h at a current density of 120
mA cm<sup>–2</sup>, indicating that these catalysts have both
high activity and stability for OER and HER reactions.
2019-11-19 17:06:03
vacancy
voltage
water splitting test
density
stability
hydrogen evolution reaction
electrocatalyst
cm
oxygen evolution reaction
mA
overpotential
CoFeNiO-NSA
OER
oxygen vacancies
CoFeNi-NSA
NSA
Crystalline Multi-Metal Nanosheets Array
150 h HER
Stable Bifunctional Electrocatalysts
Enriched Oxygen Vacancies
mV