Near-infrared driven N2 fixation on ZnO–MXene (Ti3C2) heterostructures through pyroelectric catalysis†

Abstract

Temperature fluctuations caused by sunlight represent a form of low-quality thermal energy that is generally insufficient for driving chemical reactions. Here, we designed a ZnO–MXene (Ti₃C₂) heterostructure catalyst, which can harvest solar near-infrared (NIR) energy to drive the sluggish ammonia production reaction using water and N₂ as the feedstock. Our research confirmed that ammonia was produced through a pyroelectric process, rather than a photocatalytic process. The ZnO–MXene heterostructure with ∼20 wt% of Ti₃C₂ exhibited a 6.5-fold improvement in activity compared to bare ZnO. The Ti₃C₂ not only harvests NIR energy to heat up the pyroelectric ZnO, but also traps the pyro electrons from ZnO and co-catalyzes the reduction of N₂ to ammonia. This work offers a novel strategy for ammonia production utilizing the abundant solar NIR energy under ambient conditions.