Reduced graphene oxide supported cobalt-calcium phosphate composite for electrochemical water oxidation

Keunyoung Lee; Wonseok Yang; Eunji Pyo; Hyebin Choi; Yeona Cha; Seonhong Lee; Chung Soo Kim; Dong Kwon Lim; Ki Young Kwon

doi:10.3390/catal11080960

Reduced graphene oxide supported cobalt-calcium phosphate composite for electrochemical water oxidation

Keunyoung Lee, Wonseok Yang, Eunji Pyo, Hyebin Choi, Yeona Cha, Seonhong Lee, Chung Soo Kim, Dong Kwon Lim, Ki Young Kwon

KU-KIST Graduate School of Converging Science and Technology

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

2 Citations (Scopus)

Abstract

We report the oxygen evolution reaction (OER) catalyst composed of cobalt–calcium phosphate on reduced graphene oxide (CoCaP/rGO). Our catalyst is prepared by the anodic electrolysis of calcium phosphate/rGO mixture loaded on indium-tin-oxide (ITO) in Co²⁺ aqueous solution. TEM, XPS and XRD experiments confirm that the crystal phase of calcium phosphate (CaP) is transferred into an amorphous phase of calcium oxide with phosphate (5.06 at%) after anodic electrolysis. Additionally, the main cation component of calcium is replaced by cobalt ion. The current–voltage characteristics of CoCaP/rGO showed a shoulder peak at 1.10 V vs. NHE, which originated from Co²⁺ to higher oxidation states (Co³⁺ or Co⁴⁺) and a strong wave from water oxidation higher +1.16 V vs. NHE at neutral condition (pH 7). CoCaP and CoCaP/rGO showed 4.8 and 10 mA/cm² at 0.47 V of overpotential, respectively. The enhanced OER catalytic activity of CoCaP/rGO arises from the synergetic interaction between the amorphous phase of CoCaP and electric conducting graphene sheets.

Original language	English
Article number	960
Journal	Catalysts
Volume	11
Issue number	8
DOIs	https://doi.org/10.3390/catal11080960
Publication status	Published - 2021 Aug

Bibliographical note

Funding Information:
Funding: This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Education (NRF-2019R1I1A3A0105983712, K.-Y.K.) and National Research Fund of Korea (2018R1A2A3075499, D.-K.L.).

Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Keywords

Calcium phosphate
Graphene
OER

ASJC Scopus subject areas

Environmental Science(all)
Catalysis
Physical and Theoretical Chemistry

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10.3390/catal11080960

Cite this

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title = "Reduced graphene oxide supported cobalt-calcium phosphate composite for electrochemical water oxidation",

abstract = "We report the oxygen evolution reaction (OER) catalyst composed of cobalt–calcium phosphate on reduced graphene oxide (CoCaP/rGO). Our catalyst is prepared by the anodic electrolysis of calcium phosphate/rGO mixture loaded on indium-tin-oxide (ITO) in Co2+ aqueous solution. TEM, XPS and XRD experiments confirm that the crystal phase of calcium phosphate (CaP) is transferred into an amorphous phase of calcium oxide with phosphate (5.06 at%) after anodic electrolysis. Additionally, the main cation component of calcium is replaced by cobalt ion. The current–voltage characteristics of CoCaP/rGO showed a shoulder peak at 1.10 V vs. NHE, which originated from Co2+ to higher oxidation states (Co3+ or Co4+) and a strong wave from water oxidation higher +1.16 V vs. NHE at neutral condition (pH 7). CoCaP and CoCaP/rGO showed 4.8 and 10 mA/cm2 at 0.47 V of overpotential, respectively. The enhanced OER catalytic activity of CoCaP/rGO arises from the synergetic interaction between the amorphous phase of CoCaP and electric conducting graphene sheets.",

keywords = "Calcium phosphate, Graphene, OER",

author = "Keunyoung Lee and Wonseok Yang and Eunji Pyo and Hyebin Choi and Yeona Cha and Seonhong Lee and Kim, {Chung Soo} and Lim, {Dong Kwon} and Kwon, {Ki Young}",

note = "Funding Information: Funding: This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Education (NRF-2019R1I1A3A0105983712, K.-Y.K.) and National Research Fund of Korea (2018R1A2A3075499, D.-K.L.). Publisher Copyright: {\textcopyright} 2021 by the authors. Licensee MDPI, Basel, Switzerland.",

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doi = "10.3390/catal11080960",

language = "English",

volume = "11",

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T1 - Reduced graphene oxide supported cobalt-calcium phosphate composite for electrochemical water oxidation

AU - Lee, Keunyoung

AU - Yang, Wonseok

AU - Pyo, Eunji

AU - Choi, Hyebin

AU - Cha, Yeona

AU - Lee, Seonhong

AU - Kim, Chung Soo

AU - Lim, Dong Kwon

AU - Kwon, Ki Young

N1 - Funding Information: Funding: This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Education (NRF-2019R1I1A3A0105983712, K.-Y.K.) and National Research Fund of Korea (2018R1A2A3075499, D.-K.L.). Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

PY - 2021/8

Y1 - 2021/8

N2 - We report the oxygen evolution reaction (OER) catalyst composed of cobalt–calcium phosphate on reduced graphene oxide (CoCaP/rGO). Our catalyst is prepared by the anodic electrolysis of calcium phosphate/rGO mixture loaded on indium-tin-oxide (ITO) in Co2+ aqueous solution. TEM, XPS and XRD experiments confirm that the crystal phase of calcium phosphate (CaP) is transferred into an amorphous phase of calcium oxide with phosphate (5.06 at%) after anodic electrolysis. Additionally, the main cation component of calcium is replaced by cobalt ion. The current–voltage characteristics of CoCaP/rGO showed a shoulder peak at 1.10 V vs. NHE, which originated from Co2+ to higher oxidation states (Co3+ or Co4+) and a strong wave from water oxidation higher +1.16 V vs. NHE at neutral condition (pH 7). CoCaP and CoCaP/rGO showed 4.8 and 10 mA/cm2 at 0.47 V of overpotential, respectively. The enhanced OER catalytic activity of CoCaP/rGO arises from the synergetic interaction between the amorphous phase of CoCaP and electric conducting graphene sheets.

AB - We report the oxygen evolution reaction (OER) catalyst composed of cobalt–calcium phosphate on reduced graphene oxide (CoCaP/rGO). Our catalyst is prepared by the anodic electrolysis of calcium phosphate/rGO mixture loaded on indium-tin-oxide (ITO) in Co2+ aqueous solution. TEM, XPS and XRD experiments confirm that the crystal phase of calcium phosphate (CaP) is transferred into an amorphous phase of calcium oxide with phosphate (5.06 at%) after anodic electrolysis. Additionally, the main cation component of calcium is replaced by cobalt ion. The current–voltage characteristics of CoCaP/rGO showed a shoulder peak at 1.10 V vs. NHE, which originated from Co2+ to higher oxidation states (Co3+ or Co4+) and a strong wave from water oxidation higher +1.16 V vs. NHE at neutral condition (pH 7). CoCaP and CoCaP/rGO showed 4.8 and 10 mA/cm2 at 0.47 V of overpotential, respectively. The enhanced OER catalytic activity of CoCaP/rGO arises from the synergetic interaction between the amorphous phase of CoCaP and electric conducting graphene sheets.

KW - Calcium phosphate

KW - Graphene

KW - OER

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JO - Catalysts

JF - Catalysts

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ER -

Reduced graphene oxide supported cobalt-calcium phosphate composite for electrochemical water oxidation

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

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