Work

New Insights into the Hydrogen Evolution Mechanism near the Ni/YSZ Triple Phase Boundary during Steam Electrolysis: A Patterned Model Electrode Study

Year: 2024

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide Solid oxide cell technologies play a crucial role in climate change mitigation by enabling the reversible storage of renewable energy. Understanding the electrochemical high-temperature reaction mechanisms and the catalytic role of the electrode and electrolyte materials is essential for advancing power-to-H 2 technologies. Despite its significance, limited in situ spectroscopic research focusing on nickel and yttria-stabilized zirconia (Ni/YSZ) is available. We employ near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) to investigate 2D porous Ni/YSZ model electrodes with variable YSZ domain sizes and triple phase boundary (TPB) lengths. Focusing on the hydrogen evolution reaction (HER), we provide a mechanistic explanation for why surface hydroxylation and electrochemical activity are correlated with the YSZ surface area and YSZ domain size and unravel the specific mechanistic role of the YSZ surface. A direct comparison of normalization of the measured total electrolysis current to the purely geometrical length of the TPB vs an electrified “catchment area” next to the TPB, exhibiting strong enough electric fields, is the key to a correct quantitative description of the individual elementary steps of water electrolysis on Ni/YSZ. By combining electrochemical impedance spectroscopy, NAP-XPS, and electric field modeling, the local water reduction process near the TPB can be described, indicating optimized structural parameters for improved HER performance.

Source: ACS electrochemistry.

DOI: 10.1021/acselectrochem.4c00031

Authors: Christoph W. Thurner, Kevin Ploner, Daniel Werner, Simon Penner, Engelbert Portenkirchner, Bernhard Klötzer

Institutions: Universität Innsbruck, Ceratizit (Luxembourg), Plansee (Austria)

Language: English

Topic: Advancements in Solid Oxide Fuel Cells

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: hybrid

Estimated APC paid: $4,500