x , generating high-grade, carbon-free heat for steel, cement and chemicals. Credit: College of Design and Engineering at NUS"> A single-atom platinum catalyst lights ammonia at 200 °C and keeps it burning steadily at 1,100 °C with low NO x , generating high-grade, carbon-free heat for steel, cement and chemicals. Credit: College of Design and Engineering at NUS A single-atom platinum catalyst lights ammonia at 200 °C and keeps it burning steadily at 1,100 °C with low NO x , generating high-grade, carbon-free heat for steel, cement and chemicals. Ammonia is a tempting fuel for the world's hottest jobs. It can be made from air, water and renewable electricity, stored as a liquid and shipped using know-how industry already has. However, the snag is that it is stubborn to ignite, burns sluggishly and tends to spew nitrogen oxides (NO x ) when pushed to high temperatures. That mix has kept heavy industry—where high-grade heat is non-negotiable—tethered to fossil fuels.…