  Nanomaterial synthesis and characterization advancements have led to the
discovery of new carbon allotropes, such as the biphenylene network (BPN). BPN
consists of four-, six-, and eight-membered rings of sp2-hybridized carbon
atoms. Here, we employ density functional theory (DFT) calculations to
investigate the CO2 adsorption capabilities in pristine and vacancy-endowed BPN
monolayers. Our findings indicate that BPN lattices with a single-atom vacancy
exhibit higher CO2 adsorption energies than pristine BPN. Unlike other 2D
carbon allotropes, BPN does not exhibit precise CO2 sensing and selectivity by
altering its band structure configuration. In pristine lattices, CO2 molecules
are physisorbed in the eight-membered rings, while defective regions of
vacancy-endowed lattices enable chemisorption of CO2. Regarding CO2
physisorption, the recovery time values are minimal, suggesting a rapid
interaction between BPN and this molecule, with negligible relaxation time
required to alter the electronic properties of BPN lattices.
