Green hydrogen: CeNS unveil new catalyst that transforms itself

Scientists at the Centre for Nano and Soft Matter Sciences (CeNS), in a collaborative effort, have unveiled a catalyst whose structure can transform itself while triggering the electrolysis of water to produce green hydrogen. This could pave the way for efficient, durable and cost-effective hydrogen production systems.

According to the Department of Science and Technology, one of the simplest ways to produce hydrogen, the clean fuel of the future, is by splitting water using electricity.

However this process only works well if there are good catalysts that make the reaction faster and more efficient.

“People assume that catalysts are fixed and stable, doing their job without changing. In reality, many catalysts behave quite differently when they are actually in use. Their structure can shift during the reaction, and these changes can have a big impact on how well they work,” the department said.

The research team, led by Neena S. John and Ph.D. scholar Palash Jyoti Gogoi from CeNS, in collaboration with Chandraraj Alex from Kiel University, Germany, and Satadeep Bhattacharjee and Swetarekha Ram from the Indo-Korea Science and Technology Centre (IKST), Bengaluru, has unveiled how the structure of the catalyst can transform itself while triggering the electrolysis of water to produce green hydrogen.

The team has provided new insights into the behaviour of molybdenum carbide (Mo2C), a widely studied earth-abundant catalyst, by uncovering how its structure evolves during the hydrogen evolution reaction (HER).

Through a combination of advanced experimental techniques, including in situ X-ray absorption spectroscopy (XAS) and in situ Raman spectroscopy, along with theoretical calculations, the researchers tracked how Mo2C changes during the HER.

The study demonstrates that Mo2C does not remain structurally static during HER, instead, it undergoes dynamic reconstruction, forming oxygen-deficient molybdenum oxide (MoOx) domains.

“These reconstructed species exhibit a local coordination environment that closely resembles MoO2 and play a decisive role in facilitating hydrogen (H2) generation. Importantly, this transformation is not detrimental but rather beneficial, leading to improved activity and stability. In contrast, Mo/Mo2C heterostructures exhibit faster oxidation, resulting in the formation of soluble molybdate species and a consequent loss of catalytic activity. This comparison clearly demonstrates that controlled reconstruction in Mo2C promotes catalytic efficiency, whereas uncontrolled oxidation in Mo/Mo2C leads to degradation,” the department said.