A laboratory-based electrochemical NAP-XPS system for operando electrocatalysis studies

Vacuum, vol. 231, pp. 113755

Abstract

During electrocatalytic reactions, the electrode, adsorbates, electrolyte ions, and solvent molecules at the electrode-electrolyte interface each play an important role. Electrochemical X-ray photoelectron spectroscopy (XPS) holds great promise for deciphering these roles, providing the oxidation state or bonding environment of every element present at the interface. However, combining the vacuum required for XPS with the wet environment needed for electrochemistry constitutes a technical challenge, requiring purpose-built instrumentation and spectro-electrochemical cell design. Here, we present a laboratory-based electrochemical XPS instrument optimized for operando studies on nano-structured electrocatalysts. The core of the system is a 3D printed spectro-electrochemical cell containing a membrane-electrode-graphene assembly. We show that this design enables us to probe the electrode surface, interfacial water, and interfacial ions under well-defined potential control. Meanwhile, the introduction of a mesoporous membrane into the assembly enables the transport of any molecular or ionic reactant towards the working electrode, opening the way to study any aqueous phase electrocatalytic system using laboratory-based electrochemical XPS. We exemplify this for the oxygen reduction reaction. • Laboratory-based operando XPS for measurements during electrocatalytic reactions. • 3D printed spectro-electrochemical flow cell. • Compatible with any aqueous phase reaction. • Characterization of the electrode surface structure, interfacial water, and adsorbed ions demonstrated.

Authors 6

1. Hassan Javed corresponding Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden, the Netherlands

2. Kees E. Kolmeijer Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden, the Netherlands

3. Nick Klein Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden, the Netherlands

4. Jamie A. Trindell Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden, the Netherlands

5. Grégory F. Schneider Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden, the Netherlands

6. Rik Valentijn Mom corresponding Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden, the Netherlands