TY - JOUR
T1 - Selective CO2 Reduction on Zinc Electrocatalyst
T2 - The Effect of Zinc Oxidation State Induced by Pretreatment Environment
AU - Nguyen, Dang Le Tri
AU - Jee, Michael Shincheon
AU - Won, Da Hye
AU - Jung, Hyejin
AU - Oh, Hyung Suk
AU - Min, Byoung Koun
AU - Hwang, Yun Jeong
N1 - Funding Information:
The authors acknowledge the support from the Korea Institute of Science and Technology (KIST) institutional program and partly by the KU-KIST program by the Ministry of Science, ICT and Future Planning.
Publisher Copyright:
© 2017 American Chemical Society.
Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 2017/12/4
Y1 - 2017/12/4
N2 - Here, we have developed porous nanostructured Zn electrocatalysts for CO2 reduction reaction (CO2RR), fabricated by reducing electrodeposited ZnO (RE-Zn) to activate the CO2RR electrocatalytic performance. We discovered that the electrochemical activation environment using CO2-bubbled electrolyte during reducing ZnO in a pretreatment step is important for highly selective CO production over H2 production, while using Ar gas bubbling instead can lead to less CO product of the Zn-based catalyst in CO2RR later. The RE-Zn activated in CO2-bubbled electrolyte condition achieves a Faradaic efficiency of CO production (FECO) of 78.5%, which is about 10% higher than that of RE-Zn activated in Ar-bubbled electrolyte. The partial current density of CO product had more 10-fold increase with RE-Zn electrodes than that of bulk Zn foil at -0.95 V vs RHE in KHCO3. In addition, a very high FECO of 95.3% can be reached using the CO2-pretreated catalyst in KCl electrolyte. The higher amount of oxidized zinc states has been found in the high performing Zn electrode surface by high-resolution X-ray photoelectron spectroscopy studies, which suggest that oxidized zinc states induce the active sites for electrochemical CO2RR. Additionally, in pre- and post-CO2RR performance tests, the carbon deposition is also significantly suppressed on RE-Zn surfaces having a higher ratio of oxidized Zn state.
AB - Here, we have developed porous nanostructured Zn electrocatalysts for CO2 reduction reaction (CO2RR), fabricated by reducing electrodeposited ZnO (RE-Zn) to activate the CO2RR electrocatalytic performance. We discovered that the electrochemical activation environment using CO2-bubbled electrolyte during reducing ZnO in a pretreatment step is important for highly selective CO production over H2 production, while using Ar gas bubbling instead can lead to less CO product of the Zn-based catalyst in CO2RR later. The RE-Zn activated in CO2-bubbled electrolyte condition achieves a Faradaic efficiency of CO production (FECO) of 78.5%, which is about 10% higher than that of RE-Zn activated in Ar-bubbled electrolyte. The partial current density of CO product had more 10-fold increase with RE-Zn electrodes than that of bulk Zn foil at -0.95 V vs RHE in KHCO3. In addition, a very high FECO of 95.3% can be reached using the CO2-pretreated catalyst in KCl electrolyte. The higher amount of oxidized zinc states has been found in the high performing Zn electrode surface by high-resolution X-ray photoelectron spectroscopy studies, which suggest that oxidized zinc states induce the active sites for electrochemical CO2RR. Additionally, in pre- and post-CO2RR performance tests, the carbon deposition is also significantly suppressed on RE-Zn surfaces having a higher ratio of oxidized Zn state.
KW - CO production
KW - CO reduction reaction
KW - Electrocatalysis
KW - Pretreatment
KW - Zinc catalyst
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U2 - 10.1021/acssuschemeng.7b02460
DO - 10.1021/acssuschemeng.7b02460
M3 - Article
AN - SCOPUS:85042388798
VL - 5
SP - 11377
EP - 11386
JO - ACS Sustainable Chemistry and Engineering
JF - ACS Sustainable Chemistry and Engineering
SN - 2168-0485
IS - 12
ER -