Augmented photoelectrochemical water reduction: influence of copper vacancies and hole-transport layer on CuBi2O4 photocathode

Madhusudana Gopannagari; D. Amaranatha Reddy; Da Hye Hong; K. Arun Joshi Reddy; D. Praveen Kumar; Hyun S. Ahn; Tae Kyu Kim

doi:10.1039/d1ta09956f

Augmented photoelectrochemical water reduction: influence of copper vacancies and hole-transport layer on CuBi₂O₄ photocathode

Madhusudana Gopannagari, D. Amaranatha Reddy, Da Hye Hong, K. Arun Joshi Reddy, D. Praveen Kumar, Hyun S. Ahn, Tae Kyu Kim

Department of Chemistry

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

4 Citations (Scopus)

Abstract

A ternary metal oxide CuBi₂O₄ has received immense attention in the research field of photoelectrochemical (PEC) water or CO₂ reduction owing to its ideal optical bandgap and positive photocurrent onset potential. However, CuBi₂O₄ photocathodes have limitations regarding charge-carrier separation within and transport across the interface to an n-type FTO substrate. In this study, a novel thin Fe-doped NiO_X layer was attached to the copper vacancy-induced CuBi₂O₄ (CBO-O₂) back-interface. X-ray photoelectron and energy dispersive spectroscopies provided evidence for copper vacancies within CBO; atomic force microscopy and electrochemical impedance spectroscopy revealed improved surface conductivity and interface charge transfer between CBO-O₂ and Fe:NiO_X. The CBO-O₂ photocathode exhibits a higher hole-concentration with superior charge-separation, and the Fe:NiO_X layer acts as an efficient hole-transport layer (HTL) at the back interface. The PEC performance characteristic of the Fe:NiO_X/CBO-O₂ photocathode increased four fold than that of a conventional-heating CBO photoelectrode (CBO-Air). Additionally, the Fe:NiO_X/CBO-O₂ photocathode with a protective layer revealed about 4 h stability and 96% faradaic efficiency. The improved photocurrent of the device is attributed to the increased acceptor density in CBO and effective hole transportation across the back interface with positive-band alignment. This work provides an efficient strategy for constructing high-performance ternary metal oxide-based photocathodes/photoanodes for sustainable and environmentally friendly energy applications.

Original language	English
Pages (from-to)	6623-6635
Number of pages	13
Journal	Journal of Materials Chemistry A
Volume	10
Issue number	12
DOIs	https://doi.org/10.1039/d1ta09956f
Publication status	Published - 2022 Feb 7

Bibliographical note

Funding Information:
This work was supported by the National Research Foundation of Korea (NRF) grants funded by the Korean Government (2020R1A4A1017737). D. A. Reddy is thankful to the DST for awarding the Inspire faculty fellowship.

Publisher Copyright:
© 2022 The Royal Society of Chemistry

All Science Journal Classification (ASJC) codes

Chemistry(all)
Renewable Energy, Sustainability and the Environment
Materials Science(all)

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

Access to Document

10.1039/d1ta09956f

Cite this

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title = "Augmented photoelectrochemical water reduction: influence of copper vacancies and hole-transport layer on CuBi2O4 photocathode",

abstract = "A ternary metal oxide CuBi2O4 has received immense attention in the research field of photoelectrochemical (PEC) water or CO2 reduction owing to its ideal optical bandgap and positive photocurrent onset potential. However, CuBi2O4 photocathodes have limitations regarding charge-carrier separation within and transport across the interface to an n-type FTO substrate. In this study, a novel thin Fe-doped NiOX layer was attached to the copper vacancy-induced CuBi2O4 (CBO-O2) back-interface. X-ray photoelectron and energy dispersive spectroscopies provided evidence for copper vacancies within CBO; atomic force microscopy and electrochemical impedance spectroscopy revealed improved surface conductivity and interface charge transfer between CBO-O2 and Fe:NiOX. The CBO-O2 photocathode exhibits a higher hole-concentration with superior charge-separation, and the Fe:NiOX layer acts as an efficient hole-transport layer (HTL) at the back interface. The PEC performance characteristic of the Fe:NiOX/CBO-O2 photocathode increased four fold than that of a conventional-heating CBO photoelectrode (CBO-Air). Additionally, the Fe:NiOX/CBO-O2 photocathode with a protective layer revealed about 4 h stability and 96% faradaic efficiency. The improved photocurrent of the device is attributed to the increased acceptor density in CBO and effective hole transportation across the back interface with positive-band alignment. This work provides an efficient strategy for constructing high-performance ternary metal oxide-based photocathodes/photoanodes for sustainable and environmentally friendly energy applications.",

author = "Madhusudana Gopannagari and Reddy, {D. Amaranatha} and Hong, {Da Hye} and {Joshi Reddy}, {K. Arun} and Kumar, {D. Praveen} and Ahn, {Hyun S.} and Kim, {Tae Kyu}",

note = "Funding Information: This work was supported by the National Research Foundation of Korea (NRF) grants funded by the Korean Government (2020R1A4A1017737). D. A. Reddy is thankful to the DST for awarding the Inspire faculty fellowship. Publisher Copyright: {\textcopyright} 2022 The Royal Society of Chemistry",

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T1 - Augmented photoelectrochemical water reduction

T2 - influence of copper vacancies and hole-transport layer on CuBi2O4 photocathode

AU - Gopannagari, Madhusudana

AU - Reddy, D. Amaranatha

AU - Hong, Da Hye

AU - Joshi Reddy, K. Arun

AU - Kumar, D. Praveen

AU - Ahn, Hyun S.

AU - Kim, Tae Kyu

N1 - Funding Information: This work was supported by the National Research Foundation of Korea (NRF) grants funded by the Korean Government (2020R1A4A1017737). D. A. Reddy is thankful to the DST for awarding the Inspire faculty fellowship. Publisher Copyright: © 2022 The Royal Society of Chemistry

PY - 2022/2/7

Y1 - 2022/2/7

N2 - A ternary metal oxide CuBi2O4 has received immense attention in the research field of photoelectrochemical (PEC) water or CO2 reduction owing to its ideal optical bandgap and positive photocurrent onset potential. However, CuBi2O4 photocathodes have limitations regarding charge-carrier separation within and transport across the interface to an n-type FTO substrate. In this study, a novel thin Fe-doped NiOX layer was attached to the copper vacancy-induced CuBi2O4 (CBO-O2) back-interface. X-ray photoelectron and energy dispersive spectroscopies provided evidence for copper vacancies within CBO; atomic force microscopy and electrochemical impedance spectroscopy revealed improved surface conductivity and interface charge transfer between CBO-O2 and Fe:NiOX. The CBO-O2 photocathode exhibits a higher hole-concentration with superior charge-separation, and the Fe:NiOX layer acts as an efficient hole-transport layer (HTL) at the back interface. The PEC performance characteristic of the Fe:NiOX/CBO-O2 photocathode increased four fold than that of a conventional-heating CBO photoelectrode (CBO-Air). Additionally, the Fe:NiOX/CBO-O2 photocathode with a protective layer revealed about 4 h stability and 96% faradaic efficiency. The improved photocurrent of the device is attributed to the increased acceptor density in CBO and effective hole transportation across the back interface with positive-band alignment. This work provides an efficient strategy for constructing high-performance ternary metal oxide-based photocathodes/photoanodes for sustainable and environmentally friendly energy applications.

AB - A ternary metal oxide CuBi2O4 has received immense attention in the research field of photoelectrochemical (PEC) water or CO2 reduction owing to its ideal optical bandgap and positive photocurrent onset potential. However, CuBi2O4 photocathodes have limitations regarding charge-carrier separation within and transport across the interface to an n-type FTO substrate. In this study, a novel thin Fe-doped NiOX layer was attached to the copper vacancy-induced CuBi2O4 (CBO-O2) back-interface. X-ray photoelectron and energy dispersive spectroscopies provided evidence for copper vacancies within CBO; atomic force microscopy and electrochemical impedance spectroscopy revealed improved surface conductivity and interface charge transfer between CBO-O2 and Fe:NiOX. The CBO-O2 photocathode exhibits a higher hole-concentration with superior charge-separation, and the Fe:NiOX layer acts as an efficient hole-transport layer (HTL) at the back interface. The PEC performance characteristic of the Fe:NiOX/CBO-O2 photocathode increased four fold than that of a conventional-heating CBO photoelectrode (CBO-Air). Additionally, the Fe:NiOX/CBO-O2 photocathode with a protective layer revealed about 4 h stability and 96% faradaic efficiency. The improved photocurrent of the device is attributed to the increased acceptor density in CBO and effective hole transportation across the back interface with positive-band alignment. This work provides an efficient strategy for constructing high-performance ternary metal oxide-based photocathodes/photoanodes for sustainable and environmentally friendly energy applications.

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