Electrocatalytic activity of defined nanostructures (5-250 nm) that are established via nanoimprint lithography
Final Report Abstract
The overall objective of this work was to contribute to the fundamental understanding of the HER and HOR at Pt/Pd nanostructures on Au surfaces. This goal was pursued by the fabrication of novel electrode structures by nanoimprint techniques, i.e. nanoimprint lithography, NIL, and nanotransfer printing, nTP. These techniques were used to establish defined nanostructure arrays of Au, on which Pt was deposited electrochemically. The implementation of these nanoimprint techniques in electrochemistry with the aim to generate ordered arrays of defined nanostructures was successful. By depositing Pt nanoislands on 160nm-wide Au lines between polymer lines the spillover effect could be demonstrated: a comparison of these electrodes with Pt nanoislands on extended Au(111) electrodes showed a decreased activity of the polymer-line electrodes in the case of small Pt coverage. This is an indication for the diminishment of the spillover of hydrogen atoms to and from the Pt nanostructures (for the hydrogen oxidation reaction, HOR, and the hydrogen evolution reaction, HER, respectively) when polymer lines are present on the Au surface. Involved parameters, such as the ideal radius of the Au surface surrounding a Pt nanostructure and an influence of Pt coverage, as theoretically determined by Wang et al., were confirmed. The utilization of Au nanostructures, which are limited in a second direction, i.e. by generation of Au pillars via nTP, was also successful: the applicability of such electrode structures in an electrochemical system was demonstrated. Hence, such a structure is suitable for the systematic evaluation of involved parameters, since the width of the Au pillars can be varied successively from a minimum of approximately 15nm to several hundreds of nanometers or even micrometers. Typical problems regarding nTP such as master reusability, defect tolerance, process cost and speed have been solved utilizing a replication technique. Our working stamps are flexible enough to ensure intimate contact with the underlying substrate over large areas even in the presence of contaminating particles. Yet, the polymer is rigid enough for printing features in the sub-50-nm regime while a high yield above 99 % has been achieved repeatedly. As a consequence, the nanolithography techniques could be used to generate electrode structures with a maximum ratio of electrocatalytic activity to active material. Thus, the utilization of nanoimprinted electrode structures in an electrochemical system is highly profitable. Moreover, the nanoimprint techniques are designed for large-scale application. Thus, the demonstration of the applicability of such electrode structures in electrochemical systems is also of industrial relevance: fast and efficient pattern transfer over large areas is possible with a roll-to-roll apparatus, which is already used for conventional printing.
Publications
- Activity of Platinum Submonolayers on Defect-Rich Au(111), 14-17/11/2011, Alicante (Spain), ELCAT-Meeting “Electrocataysis: present and future”
C. Ostermayr, U. Stimming
- Activity of Platinum Submonolayers on Defect-Rich and Nanostructured Gold, 3-7/6/2012 Lübeck (Germany), 12th International Fischer Symposium on „Frontiers in Nanoelectrochemistry“
C. Ostermayr, B. Weiler, A. Seidenstücker, G. Scarpa, A. Plettl, U. Stimming
- Activity of Platinum Submonolayers on Defect-Rich and Nanostructured Gold, 5-7/7/2012, Ulm (Germany), 6th Japanese- Italian-German Meeting of Electrochemists
C. Ostermayr, B. Weiler, A. Seidenstücker, G. Scarpa, A. Plettl, U. Stimming
- Fuelling the Future: Advances in Science and Technologies for Energy Generation, Transmission and Storage, Proceedings of The Energy and Materials Research Conference 2012, Nanostructured electrodes for electrochemical systems applications, 1 (2012) 293
B. Weiler, C. Ostermayr, U. Stimming, G. Scarpa
- Activity of Platinum on Extended Gold Surfaces and on Defined Gold-Nanostructure Arrays, 30/6-5/7/2013, Liblice (Czech Republic), International Conference on Electrified Interfaces (ICEI)
C. Ostermayr, B. Weiler, R. Nagel, G. Scarpa, U. Stimming
- Electrocatalytic activity of platinum on extended gold surfaces (2014)
Cornelia Ostermayr
- Electrocatalytic activity of platinum submonolayers on defect-rich Au(111), Journal of Surface Science, 631 (2015), 229-234
C. Ostermayr, U. Stimming
(See online at https://doi.org/10.1016/j.susc.2014.08.019) - Large Area Nano-transfer Printing of Sub-50-nm Metal Nanostructures Using Lowcost Semi-flexible Hybrid Templates, Nanoscale Research Letters 11 (1) (2016)
R. D. Nagel, T. Haeberle, M. Schmidt, P. Lugli, G. Scarpa
(See online at https://doi.org/10.1186/s11671-016-1346-4) - Nanoimprint Technologies for Efficient Photocatalytic Conversion of Carbon Dioxide to Carbon Fuels, 5th International SolTech Conference 2016, München (Germany)
R.D. Nagel, T. Häberle, S. Filser, Q. Li, K. Bickel, T. Zhang, K. krischer, G. Scarpa, P. Lugli
- Nanoimprint methods for the fabrication of macroscopic plasmonically active metal nanostructures, Journal of Applied Physics 121 (8) (2017)
R. D. Nagel, S. Filser, T. Zhang, A. Manzi, K. Schönleber, J. Lindsly, J. Zimmermann, T. L. Maier, G. Scarpa, K. Krischer, P. Lugli
(See online at https://doi.org/10.1063/1.4976860)
