Reduced Graphene Oxide Supported Cobalt-Calcium Phosphate Composite for Electrochemical Water Oxidation

Reduced Graphene Oxide Supported Cobalt-Calcium Phosphate Composite for Electrochemical Water Oxidation

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 Co<sup>2+</sup> aqueous solution. TE...

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Main Authors: Keunyoung Lee, Wonseok Yang, Eunji Pyo, Hyebin Choi, Yeona Cha, Seonhong Lee, Chung Soo Kim, Dong-Kwon Lim, Ki-Young Kwon
Format: Article
Language:English
Published: MDPI AG 2021-08-01
Series:Catalysts
Subjects:
OER
calcium phosphate
graphene
Online Access:https://www.mdpi.com/2073-4344/11/8/960
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spelling doaj-c84499f044db4ba39b7a500b3cc82aae2021-08-26T13:36:38ZengMDPI AGCatalysts2073-43442021-08-011196096010.3390/catal11080960Reduced Graphene Oxide Supported Cobalt-Calcium Phosphate Composite for Electrochemical Water OxidationKeunyoung Lee0Wonseok Yang1Eunji Pyo2Hyebin Choi3Yeona Cha4Seonhong Lee5Chung Soo Kim6Dong-Kwon Lim7Ki-Young Kwon8Department of Chemistry, Gyeongsang National University, Jinju 52828, KoreaKU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, KoreaDepartment of Chemistry, Gyeongsang National University, Jinju 52828, KoreaDepartment of Chemistry, Gyeongsang National University, Jinju 52828, KoreaDepartment of Chemistry, Gyeongsang National University, Jinju 52828, KoreaAnalysis & Certification Center, Korea Institute of Ceramic Engineering & Technology, Jinju 52851, KoreaAnalysis & Certification Center, Korea Institute of Ceramic Engineering & Technology, Jinju 52851, KoreaKU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, KoreaDepartment of Chemistry, Gyeongsang National University, Jinju 52828, KoreaWe 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 Co<sup>2+</sup> 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 Co<sup>2+</sup> to higher oxidation states (Co<sup>3+</sup> or Co<sup>4+</sup>) 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/cm<sup>2</sup> 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.https://www.mdpi.com/2073-4344/11/8/960OERcalcium phosphategraphene
collection DOAJ
language English
format Article
sources DOAJ
author Keunyoung Lee
Wonseok Yang
Eunji Pyo
Hyebin Choi
Yeona Cha
Seonhong Lee
Chung Soo Kim
Dong-Kwon Lim
Ki-Young Kwon
spellingShingle Keunyoung Lee
Wonseok Yang
Eunji Pyo
Hyebin Choi
Yeona Cha
Seonhong Lee
Chung Soo Kim
Dong-Kwon Lim
Ki-Young Kwon
Reduced Graphene Oxide Supported Cobalt-Calcium Phosphate Composite for Electrochemical Water Oxidation
Catalysts
OER
calcium phosphate
graphene
author_facet Keunyoung Lee
Wonseok Yang
Eunji Pyo
Hyebin Choi
Yeona Cha
Seonhong Lee
Chung Soo Kim
Dong-Kwon Lim
Ki-Young Kwon
author_sort Keunyoung Lee
title Reduced Graphene Oxide Supported Cobalt-Calcium Phosphate Composite for Electrochemical Water Oxidation
title_short Reduced Graphene Oxide Supported Cobalt-Calcium Phosphate Composite for Electrochemical Water Oxidation
title_full Reduced Graphene Oxide Supported Cobalt-Calcium Phosphate Composite for Electrochemical Water Oxidation
title_fullStr Reduced Graphene Oxide Supported Cobalt-Calcium Phosphate Composite for Electrochemical Water Oxidation
title_full_unstemmed Reduced Graphene Oxide Supported Cobalt-Calcium Phosphate Composite for Electrochemical Water Oxidation
title_sort reduced graphene oxide supported cobalt-calcium phosphate composite for electrochemical water oxidation
publisher MDPI AG
series Catalysts
issn 2073-4344
publishDate 2021-08-01
description 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 Co<sup>2+</sup> 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 Co<sup>2+</sup> to higher oxidation states (Co<sup>3+</sup> or Co<sup>4+</sup>) 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/cm<sup>2</sup> 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.
topic OER
calcium phosphate
graphene
url https://www.mdpi.com/2073-4344/11/8/960
work_keys_str_mv AT keunyounglee reducedgrapheneoxidesupportedcobaltcalciumphosphatecompositeforelectrochemicalwateroxidation
AT wonseokyang reducedgrapheneoxidesupportedcobaltcalciumphosphatecompositeforelectrochemicalwateroxidation
AT eunjipyo reducedgrapheneoxidesupportedcobaltcalciumphosphatecompositeforelectrochemicalwateroxidation
AT hyebinchoi reducedgrapheneoxidesupportedcobaltcalciumphosphatecompositeforelectrochemicalwateroxidation
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AT chungsookim reducedgrapheneoxidesupportedcobaltcalciumphosphatecompositeforelectrochemicalwateroxidation
AT dongkwonlim reducedgrapheneoxidesupportedcobaltcalciumphosphatecompositeforelectrochemicalwateroxidation
AT kiyoungkwon reducedgrapheneoxidesupportedcobaltcalciumphosphatecompositeforelectrochemicalwateroxidation
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