Catalyst-Free Transformation of Carbon Dioxide to Small Organic Compounds in Water Microdroplets Nebulized by Different Gases.

A straightforward nebulized spray system is designed to explore the hydrogenation of carbon dioxide (CO) within water microdroplets surrounded by different gases such as carbon dioxide, nitrogen, oxygen, and compressed air. The collected droplets are analyzed using water-suppressed nuclear magnetic resonance (NMR). Formate anion (HCOO), acetate anion (CHCOO), ethylene glycol (HOCHCHOH), and methane (CH) are detected when water is nebulized. This pattern persisted when the water is saturated with CO, indicating that CO in the nebulizing gas triggers the formation of these small organics. In a pure CO atmosphere, the formate anion concentration is determined to be ≈70 µm, referenced to dimethyl sulfoxide, which has been introduced as an internal standard in the collected water droplets. This study highlights the power of water microdroplets to initiate unexpected chemistry for the transformation of CO to small organic compounds.