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

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.