Fundamental Investigations into the Activity and Stability of Iron-Based Bimetallic Catalysts for the Oxygen Evolution Reaction
Year: 2026
Type: preprint
Abstract: Engineering electrocatalyst resistance to degradation in alkaline media remains a major challenge for developing stable, earth-abundant oxygen evolution reaction (OER) anodes. Here, we combined acid–base titration and X-ray fluorescence to quantify Fe dissolution from a series of bimettalic FexMy (oxy)hydroxides deposited on Fe foils (My = Sn, Hf, Mn, Se) at 1.66–2.11 VRHE, showing that apparently stable current densities and cycle voltametery alone can mask significant electrode degradation. After initial restructuring (~2 h), end-of-life anodes showed steady-state dissolution rates of 0.15–0.67 mgFe cm⁻² h⁻¹ near OER onset (~1.75 VRHE). Across alloys, dissolution rates and OER overpotentials correlated with the Fe–My electronegativity difference. Dissolution rates were highest for those alloys where My was less electronegative than Fe, and XPS revealed a more reduced surface with higher concentrations of hydroxoligands. Spin-polarized DFT+U shows Sn reduces neighboring Fe atoms, shifting the potential-limiting OER step to Fe–O* formation, lowering its formation free energy (consistent with a reduced OER overpotential); but elongating Fe-O bonds (perhaps accelerating dissolution). Generalizing these results toward future work, we suggest that the dissolution resistance of FeOOH surfaces may be controlled by alloy-driven modulation of their protonation state (revealed by XPS) and Fe-O bond character (probed by DFT).
Source: ChemRxiv
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: green
Funder: Syracuse University
OpenAlex ID: W7214105417