TY - JOUR

T1 - Secondary Alcohols as Rechargeable Electrofuels

T2 - Electrooxidation of Isopropyl Alcohol at Pt Electrodes

AU - Waidhas, Fabian

AU - Haschke, Sandra

AU - Khanipour, Peyman

AU - Fromm, Lukas

AU - Görling, Andreas

AU - Bachmann, Julien

AU - Katsounaros, Ioannis

AU - Mayrhofer, Karl J.J.

AU - Brummel, Olaf

AU - Libuda, Jörg

N1 - Funding Information: The authors acknowledge financial support by the German Federal Ministry of Education and Research (BMBF, Project Combined Infrared and X-ray Analytics of Energy Materials, CIXenergy 05K19WE1, and ‘Tubulyze‘ 03SF0564A), the Bavarian Ministry of Economic Affairs, Regional Development and Energy, and the Initiative and Networking Fund of the Helmholtz Association (project ExNet-0012-Phase2-3). Further financial support was given by the Helmholtz Institute Erlangen-Nürnberg for Renewable Energy and the Deutsche Forschungsgemeinschaft (DFG) within the Cluster of Excellence “Engineering of Advanced Materials” (project EXC 315) (Bridge Funding). Additional support by the DFG is acknowledged through the Research Unit FOR 1878 ‘funCOS – Functional Molecular Structures on Complex Oxide Surfaces’ and further projects (project numbers 431733372, 214951840, 322419553). Publisher Copyright: Copyright © 2020 American Chemical Society. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

PY - 2020/6/19

Y1 - 2020/6/19

N2 - Fuel cells can be operated directly by oxidation of isopropyl alcohol (IPA) to acetone (ACE). If the product ACE is hydrogenated, IPA is formed again. In this way, IPA serves as a rechargeable electrofuel. In this work, we study the oxidation of IPA at Pt electrodes using several complementary experimental methods, including cyclic voltammetry (CV), electrochemical real-time mass spectrometry (EC-RTMS), and electrochemical infrared reflection absorption spectroscopy (EC-IRRAS), in combination with density functional theory (DFT) to assign the vibrational modes of IPA and ACE. Different types of Pt electrodes are investigated, namely single crystalline Pt(111) surfaces, polycrystalline Pt, and nanostructured tubular Pt electrodes. The onset of the IPA oxidation on the Pt electrodes is observed at 0.3 VRHE, yielding ACE with high selectivity. At potentials above 0.9 VRHE, the formation of Pt oxide inhibits the reaction. The only side reaction observed is the formation of small amounts of CO2. We show that adsorbed ACE is formed at the Pt electrodes poisoning the surface. On nanotubular electrodes with high surface area, ACE stays mainly adsorbed on the surface, and only a small fraction desorbs. These observations suggest that poisoning of the Pt electrode by adsorbed ACE limits the oxidation of IPA.

AB - Fuel cells can be operated directly by oxidation of isopropyl alcohol (IPA) to acetone (ACE). If the product ACE is hydrogenated, IPA is formed again. In this way, IPA serves as a rechargeable electrofuel. In this work, we study the oxidation of IPA at Pt electrodes using several complementary experimental methods, including cyclic voltammetry (CV), electrochemical real-time mass spectrometry (EC-RTMS), and electrochemical infrared reflection absorption spectroscopy (EC-IRRAS), in combination with density functional theory (DFT) to assign the vibrational modes of IPA and ACE. Different types of Pt electrodes are investigated, namely single crystalline Pt(111) surfaces, polycrystalline Pt, and nanostructured tubular Pt electrodes. The onset of the IPA oxidation on the Pt electrodes is observed at 0.3 VRHE, yielding ACE with high selectivity. At potentials above 0.9 VRHE, the formation of Pt oxide inhibits the reaction. The only side reaction observed is the formation of small amounts of CO2. We show that adsorbed ACE is formed at the Pt electrodes poisoning the surface. On nanotubular electrodes with high surface area, ACE stays mainly adsorbed on the surface, and only a small fraction desorbs. These observations suggest that poisoning of the Pt electrode by adsorbed ACE limits the oxidation of IPA.

KW - acetone

KW - fuel cell

KW - isopropyl alcohol

KW - liquid organic hydrogen carrier

KW - platinum

KW - TIME FTIR SPECTROSCOPY

KW - LOW-INDEX

KW - METHANOL OXIDATION

KW - FUEL-CELL

KW - INFRARED-SPECTROSCOPY

KW - ELECTROCHEMICAL OXIDATION

KW - PLATINIZED PLATINUM

KW - ORGANIC HYDROGEN CARRIERS

KW - IN-SITU FTIR

KW - DODECAHYDRO-N-ETHYLCARBAZOLE

UR - http://www.scopus.com/inward/record.url?scp=85089951305&partnerID=8YFLogxK

U2 - 10.1021/acscatal.0c00818

DO - 10.1021/acscatal.0c00818

M3 - Article

AN - SCOPUS:85089951305

VL - 10

SP - 6831

EP - 6842

JO - ACS Catalysis

JF - ACS Catalysis

SN - 2155-5435

IS - 12

ER -