10.1021/acsomega.8b01143.s001
Jie Yin
Jie
Yin
Fangfang Di
Fangfang
Di
Junxue Guo
Junxue
Guo
Kaixuan Zhang
Kaixuan
Zhang
Wenli Xu
Wenli
Xu
Yunying Wang
Yunying
Wang
Shaozhen Shi
Shaozhen
Shi
Ning Chai
Ning
Chai
Chaofan Chu
Chaofan
Chu
Jiazhen Wei
Jiazhen
Wei
Wenzhi Li
Wenzhi
Li
Xin Shao
Xin
Shao
Xipeng Pu
Xipeng
Pu
Dafeng Zhang
Dafeng
Zhang
Xiaozhen Ren
Xiaozhen
Ren
Jie Wang
Jie
Wang
Jinsheng Zhao
Jinsheng
Zhao
Xianxi Zhang
Xianxi
Zhang
Xinting Wei
Xinting
Wei
Fang Wang
Fang
Wang
Huawei Zhou
Huawei
Zhou
Tuning Ni-Foam into NiOOH/FeOOH Heterostructures toward
Superior Water Oxidation Catalyst via Three-Step Strategy
American Chemical Society
2018
NiOOH
water oxidation catalysts
water oxidation
Three-Step Strategy Splitting
RuO x catalysts
Hydrogen-to-oxygen volume ratios
water splitting
Superior Water Oxidation Catalyst
water oxidation activity
heterostructure
charge transfer resistance
2018-09-11 17:54:22
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Tuning_Ni-Foam_into_NiOOH_FeOOH_Heterostructures_toward_Superior_Water_Oxidation_Catalyst_via_Three-Step_Strategy/7074752
Splitting of water into hydrogen
and oxygen has become a strategic
research topic. In the two semi-reactions of water splitting, water
oxidation is preferred to the four-electron-transfer process with
a higher overpotential (η) and is the decisive step in water
splitting. Therefore, efficient water oxidation catalysts must be
developed. IrO<i><sub>x</sub></i> and RuO<i><sub>x</sub></i> catalysts are currently the most efficient catalysts in
water oxidation. However, the limited reserve and high prices of precious
metals, such as Ir and Ru, limit future large-scale industrial production
of water oxidation catalysts. In this study, we tune inert Ni-foam
into highly active NiOOH/FeOOH heterostructures as water oxidation
catalysts via three-step strategy (surface acid-treating, electroplating,
and electrooxidation). NiOOH/FeOOH heterostructures as water oxidation
catalysts only require η of 257 mV to reach a current density
of 10 mA cm<sup>–2</sup>, which is superior to that of IrO<sub>2</sub>/Ni-foam (280 mV). The high electrochemically active surface
area (72.50 cm<sup>2</sup>) and roughness factor demonstrate abundant
interfaces in NiOOH/FeOOH heterostructures, thus accelerating water
oxidation activity. The small value (4.8 Ω cm<sup>2</sup>) of
charge transfer resistance (<i>R</i><sub>ct</sub>) indicate
that fast electronic exchange occurs between NiOOH/FeOOH heterostructures
catalyst and reaction of water oxidation. Hydrogen-to-oxygen volume
ratios (approximately 2:1) indicate an almost overall water splitting
by the double-electrode system. Faraday efficiency of H<sub>2</sub> or O<sub>2</sub> is close to 90% at 2:1 hydrogen-to-oxygen volume
ratio. NiOOH/FeOOH heterostructures exhibit good stability. The results
provide significance in fundamental research and practical applications
in solar water splitting, artificial photoelectrochemical cells, and
electrocatalysts.