Why Reversing the Haber-Bosch Process Requires a New Catalyst

In this episode of Innovate and React, I met with Malte Behrens, a professor of inorganic solid-state chemistry at the University of Kiel, to discuss ammonia as a vital carrier for the hydrogen economy. We explore the challenges of transporting pure hydrogen and how converting it into ammonia offers a more practical, carbon-free solution due to its ease of liquefaction and higher volumetric energy density. Malte shares his journey from solid-state chemistry to heterogeneous catalysis. The conversation dives deep into the necessity of discovering effective and scalable catalysts to decompose, or "crack" ammonia back into hydrogen gas for energy use and nitrogen. The discussion highlights the limitations of using traditional iron catalysts, as well as the economic barriers of using highly active but expensive ruthenium. To solve this, Malte’s research focuses on alloying iron with cobalt to prevent bulk nitridation, effectively finding the optimal balance of binding energy on the Sabatier volcano curve. The episode concludes with a look at the future of green ammonia, emphasizing the need for renewable energy-driven electrolysis to power a sustainable global energy trade.