Since the 1940s, researchers had been perplexed by a chemical reaction that sometimes popped up in compost piles. The reaction happens when light hits two compounds: the nitrogen in our atmosphere and titanium dioxide, a naturally occurring mineral. The result is ammonia, a key ingredient in fertilizers. But scientists struggled to understand why this happened and replicate it in a lab. Recently, researchers from the Georgia Institute of Technology solved the mystery. Titanium dioxide must be contaminated with carbon, which is abundant in compost. That’s why decades of sterile lab experimentation never worked. If experts can harness this reaction, they could use it to make ammonia with free nitrogen and light from nature, potentially increasing sustainability and lowering the cost of fertilizers worldwide.
[This story originally appeared in print as "A New Way to Make Fertilizer?"]