Reinforcing 2D Single-Crystal Bi 2 O 2 CO 3 with Additional Interlayer Carbonates by CO 2 -Assisted Solid-to-Solid Phase Transition.

A facile gaseous CO 2 mediated solid-to-solid transformation principle is adopted to insert additional CO 3 2- anions into the thin single-crystal nanosheets of Bi 2 O 2 CO 3 , which is built of periodic arrays of intrinsic CO 3 2- anions and (Bi 2 O 2 ) 2+ layers. The additional CO 3 2- anions create abundant defects. The Bi 2 O 2 CO 3 nanosheets with rich interlayer CO 3 2- exhibit superior electronic properties and charge transfer kinetics than the pristine single-crystal 2D Bi 2 O 2 CO 3 and display enhanced catalytic activity in photocatalytic CO 2 reduction reaction and the photocatalytic oxidative degradation of organic pollutants. This work thus illustrates interlayer engineering as a flexible means to build layered 2D materials with excellent properties.