Researchers at the Ulsan National Institute of Science and Technology (UNIST) in South Korea have developed a pioneering process that enables 100% pure hydrogen to be produced from ammonia at low temperatures, offering a significant breakthrough for the global hydrogen economy. The process dramatically lowers energy use while introducing a sustainable pathway that integrates recycled silicon from discarded solar panels.

The team’s innovative technique relies on a mechanochemical reaction carried out through ball milling, which completes ammonia decomposition and hydrogen release at just 122°F (50°C). In contrast, conventional ammonia-cracking technologies require temperatures between 752°F (400°C) and 1112°F (600°C) and additional purification steps to remove nitrogen impurities. This new approach eliminates the need for costly purification, delivering both energy and cost savings.

Ammonia is increasingly recognised as an efficient hydrogen carrier due to its high hydrogen density and established global infrastructure for storage and transport. However, traditional hydrogen extraction from ammonia has been energy-intensive, limiting its scalability. The UNIST method addresses this issue by creating a self-purifying system that separates nitrogen directly within the reaction process.

In the experiment, ammonia gas and finely powdered silicon were placed inside a ball mill—a sealed container filled with ceramic or steel beads. When vigorously shaken, mechanical friction and impact activated the silicon powder, triggering ammonia decomposition. The nitrogen byproduct immediately reacted with the silicon to form solid silicon nitride, which remained in the system instead of contaminating the hydrogen output. 

Notably, the process was found to perform equally well using silicon recovered from end-of-life solar panels, turning photovoltaic waste into a valuable input for clean hydrogen production. This creates a circular sustainability model that addresses both energy generation and e-waste management. The formation of silicon nitride, a key material for secondary batteries, adds further economic value.

By combining low-temperature efficiency, hydrogen purity, and material recyclability, the process positions itself as a transformative advancement in clean energy technology - offering a scalable solution that bridges renewable fuel innovation with circular resource utilisation.

Source: 

https://interestingengineering.com/energy/recycled-solar-panel-pure-hydrogen