# In search for non precious metal oxide electrodes with the case of BaMoO3 thin films for hydrogen evolution reaction

## TL;DR

This paper explores the use of BaMoO3 thin films as a low-cost catalyst for hydrogen production but finds they degrade quickly, highlighting the need for stability testing in catalyst development.

## Contribution

The study emphasizes the importance of stability assessment and materials characterization in evaluating non-precious metal oxide catalysts for hydrogen evolution.

## Key findings

- BaMoO3 thin films show low electrochemical activity for hydrogen evolution reaction.
- The films rapidly degrade under HER conditions, contrary to previous expectations.
- Processing conditions significantly affect both activity and stability of the material.

## Abstract

Non-precious metal oxides are inexpensive catalysts for hydrogen evolution reaction (HER) in water electrolysis to realize the global-scale green hydrogen production. Here, we report on perovskite BaMoO3 thin films fabricated by pulsed laser deposition. The metallic films, grown on single crystalline NdGaO3 substrates, have the expected stoichiometry, are crystalline, and epitaxially grown in (001) direction. Relatively low electrochemical activity is found and the thin films rapidly degrade under HER conditions, contrary to expectations from the literature. Our research highlights that the processing conditions and the processing related properties of a material can have considerable effect not only on the activity, but also on the stability. In particular, stability assessment is key in identifying promising, alternative HER catalysts. In search for alternative materials, degradation needs to be investigated from the very first and specifically include catalyst characterization after electrochemical aging experiments. Attention must be paid to investigate the intrinsic properties of a material, to be aware of processing related properties of a catalyst, and to complement the performance analysis with detailed materials characterization.

The online version contains supplementary material available at 10.1038/s41598-025-21707-x.