Selective CO2 Reduction on Zinc Electrocatalyst: The Effect of Zinc Oxidation State Induced by Pretreatment Environment

Title
Selective CO2 Reduction on Zinc Electrocatalyst: The Effect of Zinc Oxidation State Induced by Pretreatment Environment
Authors
민병권황윤정오형석원다혜지신천당 리 트리 뉴옌정혜진
Keywords
CO2 reduction reaction; Zn catalyst; CO produciton; Electrocatalysis; Pretreatment
Issue Date
2017-12
Publisher
ACS sustainable chemistry & engineering
Citation
VOL 5, NO 12-11386
Abstract
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 Znbased 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 Xray 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.
URI
http://pubs.kist.re.kr/handle/201004/68047
ISSN
2168-0485
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KIST Publication > Article
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