Origin of High-Efficiency Photoelectrochemical Water Splitting on Hematite/Functional Nanohybrid Metal Oxide Overlayer Photoanode after a Low Temperature Inert Gas Annealing Treatment

Socman Ho-Kimura; Benjamin A.D. Williamson; Sanjayan Sathasivam; Savio J.A. Moniz; Guanjie He; Wenjun Luo; David O. Scanlon; Ivan P. Parkin; Tang Junwang

doi:10.1021/acsomega.8b02444

Origin of High-Efficiency Photoelectrochemical Water Splitting on Hematite/Functional Nanohybrid Metal Oxide Overlayer Photoanode after a Low Temperature Inert Gas Annealing Treatment

Socman Ho-Kimura^*, Benjamin A.D. Williamson, Sanjayan Sathasivam, Savio J.A. Moniz, Guanjie He, Wenjun Luo, David O. Scanlon, Ivan P. Parkin, Tang Junwang

^*Corresponding author for this work

Chemistry

Research output: Contribution to journal › Article › peer-review

Abstract

A simplistic and low-cost method that dramatically improves the performance of solution-grown hematite photoanodes for solar-driven water splitting through incorporation of nanohybrid metal oxide overlayers was developed. By heating the α-Fe₂O₃/SnO₂-TiO₂ electrode in an inert atmosphere, such as argon or nitrogen, the photocurrent increased to over 2 mA/cm² at 1.23 V versus a reversible hydrogen electrode, which is 10 times higher than that of pure hematite under 1 sun (100 mW/cm², AM 1.5G) light illumination. For the first time, we found a significant morphological difference between argon and nitrogen gas heat-treated hematite films and discussed the consequences for photoresponse. The origin for the enhancement, probed via theoretical modeling, stems from the facile incorporation of low formation energy dopants into the Fe₂O₃ layer at the interface of the metal oxide nanohybrid overlayer, which decreases recombination by increasing the electrical conductivity of Fe₂O₃. These dopants diffuse from the overlayer into the α-Fe₂O₃ layer readily under inert gas heat treatment. This simple yet effective strategy could be applied to other dopants to increase hematite performance for solar energy conversion applications.

Original language	English
Pages (from-to)	1449-1459
Number of pages	11
Journal	ACS Omega
Volume	4
Issue number	1
DOIs	https://doi.org/10.1021/acsomega.8b02444
Publication status	Published - 16 Jan 2019

Bibliographical note

Funding Information:
S.H.-K. thanks the support of the Science and Technology Development Fund from Macau SAR (FDCT 101/2017/A). EPSRC are thanked for funding under the Low Carbon Fuels grant no. EP/N009533/1 by S.J.A.M. G.H. acknowledges the UCL-CSC scholarship. This work made use of the ARCHER UK National Supercomputing Service (http://www.archer.ac. uk) via our membership of the UK’s HEC Materials Chemistry Consortium, which is also funded by the EPSRC (EP/ L000202). The UCL Legion and Grace HPC Facilities (Legion@UCL and Grace@UCL) were also used in the completion of this work. D.O.S. would like to acknowledge support from the EPSRC (EP/N01572X/1). S.H.-K. also thanks Prof. Tang, Z.; Dr. Hui, K.; Yang, Y.; and Xu, J. for lab support at the UM.

Publisher Copyright:
© 2019 American Chemical Society.

ASJC Scopus subject areas

General Chemistry
General Chemical Engineering

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Ho-Kimura, S., Williamson, B. A. D., Sathasivam, S., Moniz, S. J. A., He, G., Luo, W., Scanlon, D. O., Parkin, I. P., & Junwang, T. (2019). Origin of High-Efficiency Photoelectrochemical Water Splitting on Hematite/Functional Nanohybrid Metal Oxide Overlayer Photoanode after a Low Temperature Inert Gas Annealing Treatment. ACS Omega, 4(1), 1449-1459. https://doi.org/10.1021/acsomega.8b02444

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title = "Origin of High-Efficiency Photoelectrochemical Water Splitting on Hematite/Functional Nanohybrid Metal Oxide Overlayer Photoanode after a Low Temperature Inert Gas Annealing Treatment",

abstract = "A simplistic and low-cost method that dramatically improves the performance of solution-grown hematite photoanodes for solar-driven water splitting through incorporation of nanohybrid metal oxide overlayers was developed. By heating the α-Fe2O3/SnO2-TiO2 electrode in an inert atmosphere, such as argon or nitrogen, the photocurrent increased to over 2 mA/cm2 at 1.23 V versus a reversible hydrogen electrode, which is 10 times higher than that of pure hematite under 1 sun (100 mW/cm2, AM 1.5G) light illumination. For the first time, we found a significant morphological difference between argon and nitrogen gas heat-treated hematite films and discussed the consequences for photoresponse. The origin for the enhancement, probed via theoretical modeling, stems from the facile incorporation of low formation energy dopants into the Fe2O3 layer at the interface of the metal oxide nanohybrid overlayer, which decreases recombination by increasing the electrical conductivity of Fe2O3. These dopants diffuse from the overlayer into the α-Fe2O3 layer readily under inert gas heat treatment. This simple yet effective strategy could be applied to other dopants to increase hematite performance for solar energy conversion applications.",

author = "Socman Ho-Kimura and Williamson, {Benjamin A.D.} and Sanjayan Sathasivam and Moniz, {Savio J.A.} and Guanjie He and Wenjun Luo and Scanlon, {David O.} and Parkin, {Ivan P.} and Tang Junwang",

note = "Funding Information: S.H.-K. thanks the support of the Science and Technology Development Fund from Macau SAR (FDCT 101/2017/A). EPSRC are thanked for funding under the Low Carbon Fuels grant no. EP/N009533/1 by S.J.A.M. G.H. acknowledges the UCL-CSC scholarship. This work made use of the ARCHER UK National Supercomputing Service (http://www.archer.ac. uk) via our membership of the UK{\textquoteright}s HEC Materials Chemistry Consortium, which is also funded by the EPSRC (EP/ L000202). The UCL Legion and Grace HPC Facilities (Legion@UCL and Grace@UCL) were also used in the completion of this work. D.O.S. would like to acknowledge support from the EPSRC (EP/N01572X/1). S.H.-K. also thanks Prof. Tang, Z.; Dr. Hui, K.; Yang, Y.; and Xu, J. for lab support at the UM. Publisher Copyright: {\textcopyright} 2019 American Chemical Society.",

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Ho-Kimura, S, Williamson, BAD, Sathasivam, S, Moniz, SJA, He, G, Luo, W, Scanlon, DO, Parkin, IP & Junwang, T 2019, 'Origin of High-Efficiency Photoelectrochemical Water Splitting on Hematite/Functional Nanohybrid Metal Oxide Overlayer Photoanode after a Low Temperature Inert Gas Annealing Treatment', ACS Omega, vol. 4, no. 1, pp. 1449-1459. https://doi.org/10.1021/acsomega.8b02444

Origin of High-Efficiency Photoelectrochemical Water Splitting on Hematite/Functional Nanohybrid Metal Oxide Overlayer Photoanode after a Low Temperature Inert Gas Annealing Treatment. / Ho-Kimura, Socman; Williamson, Benjamin A.D.; Sathasivam, Sanjayan et al.
In: ACS Omega, Vol. 4, No. 1, 16.01.2019, p. 1449-1459.

Research output: Contribution to journal › Article › peer-review

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AU - Ho-Kimura, Socman

AU - Williamson, Benjamin A.D.

AU - Sathasivam, Sanjayan

AU - Moniz, Savio J.A.

AU - He, Guanjie

AU - Luo, Wenjun

AU - Scanlon, David O.

AU - Parkin, Ivan P.

AU - Junwang, Tang

N1 - Funding Information: S.H.-K. thanks the support of the Science and Technology Development Fund from Macau SAR (FDCT 101/2017/A). EPSRC are thanked for funding under the Low Carbon Fuels grant no. EP/N009533/1 by S.J.A.M. G.H. acknowledges the UCL-CSC scholarship. This work made use of the ARCHER UK National Supercomputing Service (http://www.archer.ac. uk) via our membership of the UK’s HEC Materials Chemistry Consortium, which is also funded by the EPSRC (EP/ L000202). The UCL Legion and Grace HPC Facilities (Legion@UCL and Grace@UCL) were also used in the completion of this work. D.O.S. would like to acknowledge support from the EPSRC (EP/N01572X/1). S.H.-K. also thanks Prof. Tang, Z.; Dr. Hui, K.; Yang, Y.; and Xu, J. for lab support at the UM. Publisher Copyright: © 2019 American Chemical Society.

PY - 2019/1/16

Y1 - 2019/1/16

N2 - A simplistic and low-cost method that dramatically improves the performance of solution-grown hematite photoanodes for solar-driven water splitting through incorporation of nanohybrid metal oxide overlayers was developed. By heating the α-Fe2O3/SnO2-TiO2 electrode in an inert atmosphere, such as argon or nitrogen, the photocurrent increased to over 2 mA/cm2 at 1.23 V versus a reversible hydrogen electrode, which is 10 times higher than that of pure hematite under 1 sun (100 mW/cm2, AM 1.5G) light illumination. For the first time, we found a significant morphological difference between argon and nitrogen gas heat-treated hematite films and discussed the consequences for photoresponse. The origin for the enhancement, probed via theoretical modeling, stems from the facile incorporation of low formation energy dopants into the Fe2O3 layer at the interface of the metal oxide nanohybrid overlayer, which decreases recombination by increasing the electrical conductivity of Fe2O3. These dopants diffuse from the overlayer into the α-Fe2O3 layer readily under inert gas heat treatment. This simple yet effective strategy could be applied to other dopants to increase hematite performance for solar energy conversion applications.

AB - A simplistic and low-cost method that dramatically improves the performance of solution-grown hematite photoanodes for solar-driven water splitting through incorporation of nanohybrid metal oxide overlayers was developed. By heating the α-Fe2O3/SnO2-TiO2 electrode in an inert atmosphere, such as argon or nitrogen, the photocurrent increased to over 2 mA/cm2 at 1.23 V versus a reversible hydrogen electrode, which is 10 times higher than that of pure hematite under 1 sun (100 mW/cm2, AM 1.5G) light illumination. For the first time, we found a significant morphological difference between argon and nitrogen gas heat-treated hematite films and discussed the consequences for photoresponse. The origin for the enhancement, probed via theoretical modeling, stems from the facile incorporation of low formation energy dopants into the Fe2O3 layer at the interface of the metal oxide nanohybrid overlayer, which decreases recombination by increasing the electrical conductivity of Fe2O3. These dopants diffuse from the overlayer into the α-Fe2O3 layer readily under inert gas heat treatment. This simple yet effective strategy could be applied to other dopants to increase hematite performance for solar energy conversion applications.

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Origin of High-Efficiency Photoelectrochemical Water Splitting on Hematite/Functional Nanohybrid Metal Oxide Overlayer Photoanode after a Low Temperature Inert Gas Annealing Treatment

Abstract

Bibliographical note

ASJC Scopus subject areas

UN SDGs

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