Nitrate synthesis from charged water microdroplets and dinitrogen

Abstract

Nitrate synthesis is an important process for agriculture and industry, but suffers from energy-intensive steps including the synthesis and subsequent oxidation of ammonia. Herein, we present a selective N₂ transformation to nitrate by guiding the charge neutralization of self-electrified water microdroplets in an artificial cloud generated with the portable ultrasonic atomizer. The electron and ion transfer in the charge neutralization of water microdroplets on metal micromesh enables an up to ∼40-fold increase in the reactivity of nitrate formation reaction driven by ultrasonic energy. A robust semi-continuous N₂ oxidation by a Ni-mesh-screened cloud system was achieved, providing nitrate with ∼12 mM concentration every 20 h. These findings emphasize the potential of harnessing the microdroplet-mediated cloud electrochemistry of N₂ in decentralizing the current mass production of fertilizer.