Single-atom catalysts enabled catalytic ammonia combustion at 1,100°C

Abstract

Green ammonia (NH₃) is a promising renewable fuel but suffers from having poor combustion characteristics. High-temperature catalytic NH₃ combustion (HT-CAC) provides an attractive solution to improve the combustibility of NH₃ and allows high-quality heat to be extracted with reduced harmful emissions. Achieving HT-CAC is a difficult task due to (1) demanding stability requirements of catalysts and (2) potentially high NO_x emissions. Here, we report that atomically dispersed platinum (Pt) on 10% zirconium dioxide (ZrO₂)-aluminum oxide (Al₂O₃) can facilitate the HT-CAC process. The catalyst ignites NH₃ combustion just above 200°C and has excellent stability when operated at 1,100°C. The presence of the catalyst also reduces the NO_x emissions to around 50 ppm without detectable NH₃ slip. This work shows that combining single-atom catalysts with refractory support materials is an effective strategy for designing catalysts for HT-CAC, which will in turn help to decarbonize many “hard-to-abate” sectors, such as industrial heating.