TY - JOUR
T1 - Iridium-Functionalized Metal-Organic Framework Nanocrystals Interconnected by Carbon Nanotubes Competent for Electrocatalytic Water Oxidation
AU - Chang, Tzu En
AU - Chuang, Cheng Hsun
AU - Chen, Yu Hsiu
AU - Wang, Yi Ching
AU - Gu, Yu Juan
AU - Kung, Chung Wei
N1 - Funding Information:
This project was sponsored by Ministry of Science and Technology (MOST) of Taiwan, under projects MOST 110-2221-E-006-017-MY3. We thank the support from the Yushan Young Scholar Program, under Ministry of Education (MOE), Taiwan. This article was also supported in part by Higher Education Sprout Project, MOE, Taiwan to the Headquarters of University Advancement at National Cheng Kung University (NCKU). We also thank Kun-Hsu Lee in Instrument Center of NCKU for thin-film XRD measurements. We gratefully acknowledge the use of high-resolution TEM belonging to the Center for Micro/Nano Science and Technology of NCKU. We also appreciate Surface Analysis Lab in Department of Chemical Engineering, National Taiwan University for XPS experiments and data fitting.
Funding Information:
This project was sponsored by Ministry of Science and Technology (MOST) of Taiwan, under projects MOST 110‐2221‐E‐006‐017‐MY3. We thank the support from the Yushan Young Scholar Program, under Ministry of Education (MOE), Taiwan. This article was also supported in part by Higher Education Sprout Project, MOE, Taiwan to the Headquarters of University Advancement at National Cheng Kung University (NCKU). We also thank Kun‐Hsu Lee in Instrument Center of NCKU for thin‐film XRD measurements. We gratefully acknowledge the use of high‐resolution TEM belonging to the Center for Micro/Nano Science and Technology of NCKU. We also appreciate Surface Analysis Lab in Department of Chemical Engineering, National Taiwan University for XPS experiments and data fitting.
Publisher Copyright:
© 2022 Wiley-VCH GmbH.
PY - 2022/8/5
Y1 - 2022/8/5
N2 - Nanocrystals of a zirconium-based metal-organic framework (MOF), UiO-66, are grown on the surface of the carboxylic acid-functionalized multi-walled carbon nanotubes (CNT) at room temperature to synthesize the UiO-66-CNT nanocomposites with tunable MOF-to-CNT ratios. The porosity, crystallinity, morphology, and electrical conductivity of the nanocomposite are characterized. Spatially dispersed iridium sites are thereafter installed on the defect sites presented within the entire UiO-66 crystals in these nanocomposites by a self-limiting solution-phase approach. The resulting Ir-functionalized UiO-66, CNT, and UiO-66-CNT nanocomposites are served as the electrocatalysts for water oxidation in acidic aqueous solutions. By utilizing the redox-hopping pathways to transport electrons within the Ir-functionalized MOF crystals as well as the electronic conduction between MOF crystals provided by CNT, the nanocomposite with the optimal MOF-to-CNT ratio can outperform both the Ir-functionalized UiO-66 and CNT. Electrochemical impedance spectroscopy (EIS) is utilized to probe the reaction kinetics occurring on the decorated iridium sites and the transporting behaviors of electrons/ions within these catalytic thin films. For the first time, the electrocatalytic kinetics and the transporting limitations within the MOF-based thin film can be decoupled with the help of EIS technique. Post-electrocatalysis characterizations of the nanocomposite after water oxidation are also performed.
AB - Nanocrystals of a zirconium-based metal-organic framework (MOF), UiO-66, are grown on the surface of the carboxylic acid-functionalized multi-walled carbon nanotubes (CNT) at room temperature to synthesize the UiO-66-CNT nanocomposites with tunable MOF-to-CNT ratios. The porosity, crystallinity, morphology, and electrical conductivity of the nanocomposite are characterized. Spatially dispersed iridium sites are thereafter installed on the defect sites presented within the entire UiO-66 crystals in these nanocomposites by a self-limiting solution-phase approach. The resulting Ir-functionalized UiO-66, CNT, and UiO-66-CNT nanocomposites are served as the electrocatalysts for water oxidation in acidic aqueous solutions. By utilizing the redox-hopping pathways to transport electrons within the Ir-functionalized MOF crystals as well as the electronic conduction between MOF crystals provided by CNT, the nanocomposite with the optimal MOF-to-CNT ratio can outperform both the Ir-functionalized UiO-66 and CNT. Electrochemical impedance spectroscopy (EIS) is utilized to probe the reaction kinetics occurring on the decorated iridium sites and the transporting behaviors of electrons/ions within these catalytic thin films. For the first time, the electrocatalytic kinetics and the transporting limitations within the MOF-based thin film can be decoupled with the help of EIS technique. Post-electrocatalysis characterizations of the nanocomposite after water oxidation are also performed.
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U2 - 10.1002/cctc.202200199
DO - 10.1002/cctc.202200199
M3 - Article
AN - SCOPUS:85128550172
VL - 14
JO - ChemCatChem
JF - ChemCatChem
SN - 1867-3880
IS - 15
M1 - e202200199
ER -