Charge carrier dynamics of Earth abundant co-catalyst (Ni) modified nanorod arrays for enhanced water splitting

The vertically oriented Ni (Ni0) decorated hematite nanorod array have been synthesized. The optimal Ni loading enhances photocurrent density > 4 folds at 1.23 V vs RHE and lowers the overpotential for driving the water oxidation, by ~70 mV. The Ni decorated hematite photoelectrode shows a longer...

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Bibliographic Details
Published in:Surface & coatings technology 2018-09, Vol.349, p.540-546
Main Authors: Swain, Smrutirekha, Sahu, Aditya P., Mishra, Biswajit, Satpati, Biswarup, Basu, Suddhasatwa, Chaudhary, Yatendra S.
Format: Article
Language:English
Subjects:
Arrays
Bending
Carrier density
Catalysis
Catalysts
Charge carrier dynamics
Charge density
Charge transfer
Current carriers
Density
Hematite
Morphology
Nanorod
Nanorods
Nickel
Noble metals
Oxidation
Photocatalysts
Photoelectric effect
Photoelectric emission
Photoelectrochemical water splitting
Photoluminescence
Reaction kinetics
Separation
Studies
Water splitting
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Summary:The vertically oriented Ni (Ni0) decorated hematite nanorod array have been synthesized. The optimal Ni loading enhances photocurrent density > 4 folds at 1.23 V vs RHE and lowers the overpotential for driving the water oxidation, by ~70 mV. The Ni decorated hematite photoelectrode shows a longer decay time (~195 ps) and higher Stern-Volmer constant (5.25 M−1) than that of bare hematite photoelectrode (~156 ps and 3.89 M−1, respectively), implying an efficient charge separation and transfer across the hematite nanorod-Ni nanocrystal heterointerface. Such drastic improvement in the activity is due to the unified effects of enhanced charge separation and charge carrier densities, faster charge transfer kinetics, decreased width of depletion layer, and enhanced band bending – lead by the unison of the nanorod arrays morphology and Ni modification. These results suggest potential candidature of Earth abundant metallic Ni as a co-catalysts (-alternative to noble metals) for designing new photocatalysts. [Display omitted] •Ni0 loading enhances photocurrent density by 4 folds & lowers overpotential.•Longer decay time (~195 ps) implying improved charge separation•Higher Stern-Volmer constant (5.25 M−1) for Ni-hematite implying faster kinetics•Demonstrate candidature of Ni0 as an alternative co-catalyst to noble metals
ISSN:0257-8972
1879-3347
DOI:10.1016/j.surfcoat.2018.06.029