Adsorption energy (eV per molecule) of XO (X = N and C) molecules onto pristine and Al-doped silicene monolayers.

	XO	2XO1	2XO2	2XO3	2XO4	3XO	4XO
Onto pristine silicene
NO	−0.46	−1.22	−0.45	−0.32	−0.44	−0.48	−0.47
CO	0.16	−0.26	0.12	0.25	0.12	0.13	0.12
Onto Al-doped silicene
CO	−0.40	−0.71	−0.42	−0.45	−0.19	−0.44	−0.46