TY - JOUR
T1 - Electrolysis of Water at Atomically Tailored Epitaxial Cobaltite Surfaces
AU - Weber, Moritz L.
AU - Baeumer, Christoph
AU - Mueller, David N.
AU - Jin, Lei
AU - Jia, Chun Lin
AU - Bick, Daniel S.
AU - Waser, Rainer
AU - Dittmann, Regina
AU - Valov, Ilia
AU - Gunkel, Felix
N1 - Funding Information:
The authors thank Stefan Baumann (Institute of Energy and Climate Research 1, Forschungszentrum Juelich GmbH, 52425 Juelich, Germany) for the preparation of the ceramic LSCO target material. M.L.W. and F.G. thank René Borowski, Paul Meuffels, Volker Nischwitz, Harut Dashtoyan, and Xun Chen for their experimental support. D.N.M. gratefully acknowledges support by the Juelich Joint Redox Lab (JJRL). C.B. has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 796142.
Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/4/9
Y1 - 2019/4/9
N2 - As complex transition-metal oxides of perovskite structures, many cobaltites are active electrocatalysts promoting oxygen evolution reaction (OER) during electrochemical water splitting. To unveil specific structure-activity relationships for electrocatalytic performance, innovative types of catalysts are required to overcome the inherent high complexity of regular powder catalysts, where thin-film technology gained significance in recent years. As we demonstrate, epitaxial La 0.6 Sr 0.4 CoO 3 (LSCO) thin films can be deposited with controlled bulk properties, surface structure, and stoichiometry on orthorhombic (110) NdGaO 3 single-crystalline substrates by pulsed-laser deposition, providing ideal model systems for this purpose. The epitaxial thin films are dense and single crystalline with sub-nanometer surface roughness and grow well oriented toward the pseudocubic [001] direction. The LSCO thin films show high activity catalyzing the OER and can carry significant current density loads exceeding 100 mA/cm 2 . Using these model catalysts, X-ray photoemission spectroscopy reveals the degradation of the material under these dynamic conditions, involving cation leaching and a phase transformation of the oxide. An altered surface stoichiometry as well as cobalt hydroxide formation is observed. Our results show that epitaxial model systems can be operated at large current density loads, allowing a systematic study of catalysts and their degradation under highly dynamic conditions.
AB - As complex transition-metal oxides of perovskite structures, many cobaltites are active electrocatalysts promoting oxygen evolution reaction (OER) during electrochemical water splitting. To unveil specific structure-activity relationships for electrocatalytic performance, innovative types of catalysts are required to overcome the inherent high complexity of regular powder catalysts, where thin-film technology gained significance in recent years. As we demonstrate, epitaxial La 0.6 Sr 0.4 CoO 3 (LSCO) thin films can be deposited with controlled bulk properties, surface structure, and stoichiometry on orthorhombic (110) NdGaO 3 single-crystalline substrates by pulsed-laser deposition, providing ideal model systems for this purpose. The epitaxial thin films are dense and single crystalline with sub-nanometer surface roughness and grow well oriented toward the pseudocubic [001] direction. The LSCO thin films show high activity catalyzing the OER and can carry significant current density loads exceeding 100 mA/cm 2 . Using these model catalysts, X-ray photoemission spectroscopy reveals the degradation of the material under these dynamic conditions, involving cation leaching and a phase transformation of the oxide. An altered surface stoichiometry as well as cobalt hydroxide formation is observed. Our results show that epitaxial model systems can be operated at large current density loads, allowing a systematic study of catalysts and their degradation under highly dynamic conditions.
UR - http://www.scopus.com/inward/record.url?scp=85063583409&partnerID=8YFLogxK
U2 - 10.1021/acs.chemmater.8b04577
DO - 10.1021/acs.chemmater.8b04577
M3 - Article
AN - SCOPUS:85063583409
VL - 31
SP - 2337
EP - 2346
JO - Chemistry of materials
JF - Chemistry of materials
SN - 0897-4756
IS - 7
ER -