Scientists Discover Catalyst Changes That Boost Green Hydrogen Production

A team of scientists has uncovered how a widely used catalyst changes its structure while producing green hydrogen, a discovery that could help develop more efficient and affordable hydrogen production technologies. The research focuses on molybdenum carbide (Mo₂C), an earth-abundant catalyst that has attracted significant attention as a low-cost alternative for hydrogen generation through water electrolysis.

Scientists have long viewed catalysts as stable materials that accelerate chemical reactions without changing themselves. The new study challenges that assumption by showing that the catalyst actively transforms while the reaction takes place, and that these changes actually improve its performance. The research was led by Dr. Neena S. John and PhD scholar Palash Jyoti Gogoi from the Centre for Nano and Soft Matter Sciences (CeNS) in Bengaluru, in collaboration with researchers from Kiel University in Germany and the Indo-Korea Science and Technology Center (IKST) in Bengaluru.

Advanced techniques track catalyst behaviour in real time

Using sophisticated analytical tools, including in situ X-ray absorption spectroscopy and Raman spectroscopy, researchers observed how the catalyst behaved during the hydrogen evolution reaction (HER), a critical process in water splitting.

Their findings showed that molybdenum carbide does not remain unchanged during hydrogen production. Instead, it undergoes a dynamic restructuring process that creates oxygen-deficient molybdenum oxide (MoOx) regions on its surface. These newly formed structures closely resemble molybdenum dioxide (MoO₂) and were found to play a crucial role in accelerating hydrogen generation.

Rather than harming the catalyst, the transformation improved both its activity and long-term stability. The researchers discovered that the newly formed active phase was more effective at producing hydrogen than the original catalyst structure.

Findings could shape next-generation clean energy technologies

The study also compared pure molybdenum carbide with molybdenum/molybdenum carbide heterostructures. Researchers found that the latter experienced rapid oxidation, producing soluble molybdate compounds that reduced catalytic performance over time.

This contrast highlighted the importance of controlled structural changes. While carefully regulated reconstruction enhanced efficiency, uncontrolled oxidation led to catalyst degradation and reduced effectiveness.

The findings provide valuable insights into how catalysts operate under real-world conditions and suggest that the most active catalytic phase often develops during the reaction itself rather than existing in the original material.

Published in the journal Materials Horizons, the research establishes a direct connection between atomic-level structural changes, redox processes and catalytic performance.

Scientists believe the discovery could guide the design of next-generation electrocatalysts that are more efficient, durable and cost-effective, helping accelerate the development of green hydrogen technologies and supporting the global transition to cleaner energy sources.