Precise CO Reduction for Bilayer Graphene.

It is of great significance to explore unique and diverse chemical pathways to convert CO into high-value-added products. Bilayer graphene (BLG), with a tunable twist angle and band structure, holds tremendous promise in both fundamental physics and next-generation high-performance devices. However, the π-conjugation and precise two-atom thickness are hindering the selective pathway, through an uncontrolled CO reduction and perplexing growth mechanism. Here, we developed a chemical vapor deposition method to catalytically convert CO into a high-quality BLG single crystal with a room temperature mobility of 2346 cm V s. In a finely controlled growth window, the CO molecule works as both the carbon source and the oxygen etchant, helping to precisely define the BLG nucleus and set a record growth rate of 300 μm h.