One-step Formation of Urea from Carbon Dioxide and Nitrogen Using Water Microdroplets
Xiaowei Song, Chanbasha Basheer, Yu Xia, Juan Li, Ismail Abdulazeez, Abdulaziz A. Al‐Saadi, Mohammad Mofidfar, Mohammed A. Suliman, Richard N. Zare
Abstract
Water (H 2 O) microdroplets are sprayed onto a graphite mesh covered with a CuBi 2 O 4 coating using a 1:1 mixture of N 2 and CO 2 as the nebulizing gas. The resulting microdroplets contain urea [CO(NH 2 ) 2 ] as detected by both mass spectrometry and 13 C nuclear magnetic resonance. This gas–liquid–solid heterogeneous catalytic system synthesizes urea in one step on the 0.1 ms time scale. The conversion rate reaches 2.7 mmol g –1 h –1 at 25 °C and 12.3 mmol g –1 h –1 at 65 °C, with no external voltage applied. Water microdroplets serve as the hydrogen source and the electron transfer medium for N 2 and CO 2 in contact with CuBi 2 O 4 . Water–gas and water–solid contact electrification are speculated to drive the reaction process. This strategy couples N 2 fixation and CO 2 utilization in an ecofriendly process to produce urea, converting a greenhouse gas into a value-added product.