Optimizing Temperature Treatment of Copper Hollow Fibers for the Electrochemical Reduction of CO<sub>2</sub> to CO

Copper hollow fibers were prepared via dry-wet spinning of a polymer solution of N-methylpyrrolidone, Polyetherimide, Polyvinyl Pyrolidone, and copper particles of sizes in the range of 1–2 µm. To remove template molecules and to sinter the copper particles, the time of calcination was varied in a r...

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Main Authors: Khalid Khazzal Hummadi, Anne Sustronk, Recep Kas, Nieck Benes, Guido Mul
Format: Article
Language:English
Published: MDPI AG 2021-04-01
Series:Catalysts
Subjects:
Online Access:https://www.mdpi.com/2073-4344/11/5/571
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author Khalid Khazzal Hummadi
Anne Sustronk
Recep Kas
Nieck Benes
Guido Mul
author_facet Khalid Khazzal Hummadi
Anne Sustronk
Recep Kas
Nieck Benes
Guido Mul
author_sort Khalid Khazzal Hummadi
collection DOAJ
description Copper hollow fibers were prepared via dry-wet spinning of a polymer solution of N-methylpyrrolidone, Polyetherimide, Polyvinyl Pyrolidone, and copper particles of sizes in the range of 1–2 µm. To remove template molecules and to sinter the copper particles, the time of calcination was varied in a range of 1–4 h at 600 °C. This calcination temperature was determined based on Thermal Gravimetric Analysis (TGA), showing completion of hydrocarbon removal at this temperature. Furthermore, the temperature of the subsequent treatment of the fibers in a flow of 4% H<sub>2</sub> (in Ar) was varied in the range of 200 °C to 400 °C, at a fixed time of 1 h. Temperature programmed reduction experiments (TPR) were used to analyze the hydrogen treatment. The Faradaic Efficiency (FE) towards CO in electrochemical reduction of CO<sub>2</sub> was determined at −0.45 V vs. RHE (Reversible Hydrogen Electrode), using a 0.3 M KHCO<sub>3</sub> electrolyte. A calcination time of 3 h at 600 °C and a hydrogen treatment temperature of 280 °C were found to induce the highest FE to CO of 73% at these constant electrochemical conditions. Optimizing oxidation properties is discussed to likely affect porosity, favoring the CO<sub>2</sub> gas distribution over the length of the fiber, and hence the CO<sub>2</sub> reduction efficiency. Treatment in H<sub>2</sub> in the range of 250 to 300 °C is proposed to affect the content of residual (subsurface) oxygen in Cu, which leads to favorable properties on the nanoscale.
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spelling doaj.art-0f8d92ed653c45eaa02943ca841efe9a2023-11-21T17:48:17ZengMDPI AGCatalysts2073-43442021-04-0111557110.3390/catal11050571Optimizing Temperature Treatment of Copper Hollow Fibers for the Electrochemical Reduction of CO<sub>2</sub> to COKhalid Khazzal Hummadi0Anne Sustronk1Recep Kas2Nieck Benes3Guido Mul4College of Engineering, University of Baghdad, Aljadria, Baghdad 47024, IraqPhotocatalytic Synthesis Group, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The NetherlandsPhotocatalytic Synthesis Group, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The NetherlandsFilms in Fluids Group—Membrane Science and Technology Cluster, University of Twente, P.O. Box 217, 7500 AE Enschede, The NetherlandsPhotocatalytic Synthesis Group, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The NetherlandsCopper hollow fibers were prepared via dry-wet spinning of a polymer solution of N-methylpyrrolidone, Polyetherimide, Polyvinyl Pyrolidone, and copper particles of sizes in the range of 1–2 µm. To remove template molecules and to sinter the copper particles, the time of calcination was varied in a range of 1–4 h at 600 °C. This calcination temperature was determined based on Thermal Gravimetric Analysis (TGA), showing completion of hydrocarbon removal at this temperature. Furthermore, the temperature of the subsequent treatment of the fibers in a flow of 4% H<sub>2</sub> (in Ar) was varied in the range of 200 °C to 400 °C, at a fixed time of 1 h. Temperature programmed reduction experiments (TPR) were used to analyze the hydrogen treatment. The Faradaic Efficiency (FE) towards CO in electrochemical reduction of CO<sub>2</sub> was determined at −0.45 V vs. RHE (Reversible Hydrogen Electrode), using a 0.3 M KHCO<sub>3</sub> electrolyte. A calcination time of 3 h at 600 °C and a hydrogen treatment temperature of 280 °C were found to induce the highest FE to CO of 73% at these constant electrochemical conditions. Optimizing oxidation properties is discussed to likely affect porosity, favoring the CO<sub>2</sub> gas distribution over the length of the fiber, and hence the CO<sub>2</sub> reduction efficiency. Treatment in H<sub>2</sub> in the range of 250 to 300 °C is proposed to affect the content of residual (subsurface) oxygen in Cu, which leads to favorable properties on the nanoscale.https://www.mdpi.com/2073-4344/11/5/571copper hollow fibercalcinationhydrogenTPRCO<sub>2</sub> reduction
spellingShingle Khalid Khazzal Hummadi
Anne Sustronk
Recep Kas
Nieck Benes
Guido Mul
Optimizing Temperature Treatment of Copper Hollow Fibers for the Electrochemical Reduction of CO<sub>2</sub> to CO
Catalysts
copper hollow fiber
calcination
hydrogen
TPR
CO<sub>2</sub> reduction
title Optimizing Temperature Treatment of Copper Hollow Fibers for the Electrochemical Reduction of CO<sub>2</sub> to CO
title_full Optimizing Temperature Treatment of Copper Hollow Fibers for the Electrochemical Reduction of CO<sub>2</sub> to CO
title_fullStr Optimizing Temperature Treatment of Copper Hollow Fibers for the Electrochemical Reduction of CO<sub>2</sub> to CO
title_full_unstemmed Optimizing Temperature Treatment of Copper Hollow Fibers for the Electrochemical Reduction of CO<sub>2</sub> to CO
title_short Optimizing Temperature Treatment of Copper Hollow Fibers for the Electrochemical Reduction of CO<sub>2</sub> to CO
title_sort optimizing temperature treatment of copper hollow fibers for the electrochemical reduction of co sub 2 sub to co
topic copper hollow fiber
calcination
hydrogen
TPR
CO<sub>2</sub> reduction
url https://www.mdpi.com/2073-4344/11/5/571
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AT recepkas optimizingtemperaturetreatmentofcopperhollowfibersfortheelectrochemicalreductionofcosub2subtoco
AT nieckbenes optimizingtemperaturetreatmentofcopperhollowfibersfortheelectrochemicalreductionofcosub2subtoco
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