In the quest for clean and sustainable energy, hydrogen has emerged as a frontrunner, promising a future with reduced carbon emissions. However, producing hydrogen efficiently and cost-effectively remains a significant challenge. A recent study published in Applied Surface Science Advances, translated from English as “Advances in Surface Science,” offers a promising solution by focusing on ammonia decomposition, a process that could revolutionize hydrogen production.
Ammonia, with its high hydrogen storage capacity and established infrastructure, has long been considered a viable source for hydrogen production. However, the catalysts traditionally used in this process, particularly ruthenium, are scarce and expensive, making them impractical for large-scale commercial applications. This is where the work of Yeongjun Yoon, a researcher from the Department of Chemical Engineering and Clean-Energy Research Institute at Hanyang University in Seoul, South Korea, comes into play.
Yoon and his team have been exploring the potential of nickel (Ni) as a more cost-effective alternative to ruthenium. Nickel catalysts have shown high activity, but there’s room for improvement. To enhance their performance, the researchers turned to Ni-based alloy catalysts, combining nickel with other 3d transition metals like cobalt, copper, and iron. “By alloying nickel with these metals, we can fine-tune the catalytic properties, making the process more efficient and economical,” Yoon explains.
The team employed density functional theory (DFT) calculations to understand the catalytic activity of these metals and their alloys. They identified key reaction steps in ammonia decomposition, such as NHx‒H bond scission and nitrogen recombination, and found that nitrogen adsorption energy (Ead(N)) serves as a crucial descriptor for predicting the activation energies of these steps. This discovery led them to establish a volcano-like relationship between experimental catalytic activity and DFT-calculated Ead(N), providing a clear path for optimizing catalyst design.
One of the most exciting findings was the strong correlation between d-band filling (fd) and Ead(N). This correlation allowed the researchers to predict not only Ead(N) but also the overall catalytic activity of ammonia decomposition. Using this descriptor-based design principle, they identified Ni0.64Fe0.36 as a potentially effective and cost-efficient candidate for hydrogen production from ammonia.
The implications of this research are significant for the energy sector. As Yoon puts it, “Our findings offer valuable insights into the development of efficient, economically viable transition metal-based catalysts for hydrogen production through ammonia decomposition.” This could lead to more cost-effective and sustainable hydrogen production methods, accelerating the transition to a hydrogen-based economy.
The study, published in Applied Surface Science Advances, opens up new avenues for research and development in the field of catalytic hydrogen production. As the energy sector continues to seek cleaner and more efficient solutions, the work of Yoon and his team could play a pivotal role in shaping the future of hydrogen production. The next steps involve further experimental validation and scale-up of the Ni-based alloy catalysts, bringing us one step closer to a hydrogen-powered future.
