  By using first-principles approach, the interaction of CO${_2}$ with (001)
surfaces of six cubic ABO${_3}$ perovskites (A = Ba, Sr and B = Ti, Zr, Hf) is
studied in detail. We show that CO${_2}$ adsorption results in the formation of
highly stable CO${_3}$-like complexes with similar geometries for all
investigated compounds. This reaction leads to the suppression of the surfaces
states, opening the band gaps of the slab systems up to the corresponding bulk
energy limits. For most AO-terminated ABO${_3}$(001) perovskite surfaces, a
CO${_2}$ coverage of 0.25 was found to be sufficient to fully suppress the
surface states, whereas the same effect can only be achieved at 0.50 CO${_2}$
coverage for the BO${_2}$ terminations. The largest band gap modulation among
the AO-terminated surfaces was found for SrHfO${_3}$(001) and BaHfO${_3}$(001),
whereas the most profound effect among the BO${_2}$ terminations was identified
for SrTiO${_3}$(001) and BaTiO${_3}$(001). Based on these results and
considering practical difficulties associated with measuring conductivity of
highly resistive materials, TiO${_2}$-terminated SrTiO${_3}$(001) and
BaTiO${_3}$(001) were identified as the most prospective candidates for
chemiresistive CO${_2}$ sensing applications.
