Direct synthesis of large-area Al-doped graphene by chemical vapor deposition: Advancing the substitutionally doped graphene family

Graphene doping continues to gather momentum because it enables graphene properties to be tuned, thereby affording new properties to, improve the performance of, and expand the application potential of graphene. Graphene can be chemically doped using various methods such as surface functionalization, hybrid composites (e.g., nanoparticle decoration), and substitution doping, wherein C atoms are replaced by foreign ones in the graphene lattice. Theoretical works have predicted that graphene could be substitutionally doped by aluminum (Al) atoms, which could hold promise for exciting applications, including hydrogen storage and evolution, and supercapacitors. Other theoretical predictions suggest that Al substitutionally doped graphene (AlG) could serve as a material for gas sensors and the catalytic decomposition of undesirable materials. However, fabricating Al substitutionally doped graphene has proven challenging until now. Herein, we demonstrate how controlled-flow chemical vapor deposition (CVD) implementing a simple solid precursor can yield high-quality and large-area monolayer AlG, and this synthesis is unequivocally confirmed using various characterization methods including local electron energy-loss spectroscopy (EELS). Detailed high-resolution transmission electron microscopy (HRTEM) shows numerous bonding configurations between the Al atoms and the graphene lattice, some of which are not theoretically predicted. Furthermore, the produced AlG shows a CO₂ capturability superior to those of other substitutionally doped graphenes.