Nano- and Mesoporous Structure Formation Probed with in Situ/in Operando Small and Wide-Angle X-Ray Scattering Analysis during Electrodeposition and Dealloying Processes

Electrochemical formation of nanoporous materials by electrodeposition or dealloying is essential in various fields such as catalysis, energy storage, and sensing due to their high surface areas and controlled pore sizes. Understanding the underlying principles leading to specific morphologies during the electrochemical protocol is of importance for a directed design of desired morphologies. In situ/in operando analysis at the nanoscale, such as grazing incidence small and wide angle X-ray scattering (GISWAXS), is an important tool to understand the pathway of the structure evolution at both the mesostructural and the crystalline levels. Here the development of a versatile electrochemical cell for GISWAXS [1] was essential to be able to investigate such processes. In this presentation an overview of various projects utilizing GISWAXS is given: (i) dealloying of the binary systems AgAu and CoPd [2]; electrodeposition of (ii) vertical aligned hexagonal Pt films using liquid crystal templating with Brij®56 [3]; and (iii) mesoporous platinum nickel films using Pluronic P123 as structure directing agent, as proposed by [4]. Additionally, some current highlights in the field of electrodeposition of ordered materials will be presented. M. Bogar, I. Khalakhan, A. Gambitta, Y. Yakovlev, H. Amenitsch, In situ electrochemical grazing incidence small angle X-ray scattering: From the design of an electrochemical cell to an exemplary study of fuel cell catalyst degradation. J. Power Sources. 477, 229030 (2020). Gößler, E. Hengge, M. Bogar, M. Albu, D. Knez, H. Amenitsch, R. Würschum, In Situ Study of Nanoporosity Evolution during Dealloying AgAu and CoPd by Grazing-Incidence Small-Angle X-ray Scattering. J. Phys. Chem. C. 126, 4037–4047 (2022). P.A. Wieser, D. Moser, B. Gollas., H. Amenitsch, Monitoring of Pore Orientation by in Operando Grazing Incidence Small-Angle X-ray Scattering during Templated Electrodeposition of Mesoporous Pt Films, Acs Appl. Materials and Interfieces 15, 47604-47614 (2023). K. Eiler, S. Surinach, J. Sort, E. Pellicer, Mesoporous Ni-rich Ni–Pt thin films: Electrodeposition, characterization and performance toward hydrogen evolution reaction in acidic media, Applied Catalysis B, Environmental 265, 118597 (2020). Fig. 1 (a) Scheme of the experimental setup for monitoring electrodeposition of mesoporous PtNi via in operando GISWAXS. The incoming X-ray beam impinges on the sample at a glancing angle α i (shown in the zoomed inset into the electroch