Artificial Carbon Neutrality through Aprotic CO2 Splitting

Abstract

Global climate change mitigation necessitates global efforts to reduce CO2 emissions. Natural photosynthesis exemplifies an ingenious approach for carbon neutrality, converting CO2 into O2 and glucose through light and dark reactions. Inspired by the hydrogen-involved processes in photosynthesis, we present an aprotic electrochemical strategy for CO2 splitting into O2 and carbon using lithium as a reducing mediator. The designed electrochemical device features a gas cathode with nanoscale Co catalyst and a metallic lithium anode. When CO2 is introduced to the cathode, it undergoes a two-step lithium-related electrochemical reduction, converting it sequentially into Li2CO3 and Li2O. Li2O is then oxidized to produce O2 gas at the expense of renewable electrical energy. This process achieves an impressive O2 yield exceeding 94.7%, significantly outperforming the efficiency of natural photosynthesis. Moreover, the O2 yield can be further increased to 98.6% by employing an optimized RuCo catalyst. Our study offers a new practical and controllable pathway to produce O2 from CO2, strongly promoting the sustainable development of human society for realizing carbon neutral as well as exploring and conquering nature.