Ultraefficient Conversion of CO₂ into Morphology‐Controlled Nanocarbons: A Sustainable Strategy toward Greenhouse Gas Utilization

Abstract The ability to efficiently convert CO₂ into nanocarbons at low temperatures is highly desirable, as it would enable the environmentally benign utilization of greenhouse gases, yet this remains a considerable challenge. Herein, a one‐step, ultrafast, and scalable strategy is demonstrated to efficiently convert CO₂ into morphology‐controlled nanocarbons at low temperatures. The conversion reactions between CO₂ and LiH are achieved in less than 30 s at moderate conditions by introducing a very small amount of water, ball milling, or heating. Nanocarbons featuring wildly tunable morphology with characteristic dimensions ranging from nanoscale to macroscale are successfully synthesized by controlling the CO₂ pressure and the synthesis routes. The gas blowing velocity and its distribution are revealed as the main reasons for the CO₂ pressure and synthesis route dependent morphology and porosity of nanocarbons. Moreover, a two closed‐loop reaction process including five‐stage reactions is proposed for nanocarbons synthesis and LiH regeneration. The strategy provides a new opportunity for efficient and environmentally benign nanocarbons synthesis.