Controlled-Atmosphere Flame Fusion Growth of Nickel Poly-oriented Spherical Single Crystals—Unraveling Decades of Impossibility
Experimental research using monocrystalline electrodes has been a hallmark of interfacial electrochemistry and electrocatalysis since 1980. However, it has been limited to mainly noble metals because of the challenges encountered when using non-noble metals. We report on the development of controlled-atmosphere flame fusion that enables the growth of spherical single crystals of non-noble metals in controlled gaseous atmosphere and without the formation of surface or bulk oxides. The set-up is used to grow nickel single crystals the structure of which is verified using Laue X-ray back-scattering and scanning electron microscopy (SEM). The equilibrium shape of the nickel single crystals calculated using Wulff construction agrees with the actual shape determined using SEM. Electrochemical measurements in aqueous NaOH solution using the monocrystalline Ni electrodes reveal cyclic voltammetry features unique to their surface structure. The methodology, transferrable to other metals, creates enormous research opportunities in interfacial electrochemistry, electrocatalysis, surface science, gas-phase catalysis, and corrosion science.
KeywordsNickel single crystal Controlled atmosphere flame fusion Wulff construction Low miller index surfaces Cyclic voltammetry
We gratefully acknowledge the technical support of Charles Hearns and Patrick Given in designing and manufacturing the stainless-steel chamber bottom. We thank Drs. Gabriele Schatte and Kevin McEleney for their assistance in acquiring scanning electron microscope images. We thank Profs. Christophe Coutanceau and Stève Baranton for their assistance in manufacturing the quartz chamber.
D.E. and F.M.S. carried out all the experiments, developed the CAFF set-up and method, analyzed the data, and wrote the first version of the manuscript with equal contributions. K.L.V contributed to materials synthesis and to the electrochemical measurements. J.B. carried out the DFT calculations of the Wulff construction under the guidance of T.J. G.J. and T.J. conceived the experiments, supervised the project, analyzed the results, and contributed to the manuscript writing. All authors contributed to the discussion section and the finalization of the text and figures of the manuscript.
This research was conducted as part of the Engineered Nickel Catalysts for Electrochemical Clean Energy project administered from Queen’s University and supported by grant number RGPNM 477963-2015 under the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Frontiers Program. This work was supported by MITACS through the Globalink Research Award and the DAAD which made the collaboration between Queen’s University and Ulm University possible. This work was funded by the German Research Foundation (DFG) under project ID 390874152 (POLiS Cluster of Excellence) as well as the Sonderforschungsbereich (collaborative research centre) SFB-1316.
Compliance with Ethical Standards
The authors declare no competing interests.
The research presented in this manuscript was initially submitted to Science on June 18, 2019 and subsequently to Nature Materials on September 12, 2019. The research was presented at the 70th Annual Meeting of the International Society of Electrochemistry in Durban, South Africa, on August 8, 2019 (the respective abstract was published on the ISE website on June 25, 2019).
- 19.J. Clavilier in Interfacial electrochemistry: theory: experiment, and applications, ch. 14, ed. by A. Wieckowski (Marcel Dekker Inc., New York, 1999)Google Scholar
- 24.G. Wulff, X.X.V. Zur, Frage der Geschwindigkeit des Wachsthums und der Auflösung der Krystallflächen. Zeitschrift für Krist. Cryst. Mater. 34, 449–530 (1901)Google Scholar
- 29.N. Arulmozhi, D. Esau, J. van Drunen, G. Jerkiewicz, Design and development of instrumentations for the preparation of platinum single crystals for electrochemistry and electrocatalysis eesearch part 3: final treatment, electrochemical measurements, and recommended laboratory practices. Electrocatalysis 9, 113–123 (2018)CrossRefGoogle Scholar