Few-layer Mg-deficient borophene nanosheets: I2 oxidation and ultrasonic delamination from MgB2

Few-layer Mg-deficient borophene nanosheets with a stoichiometric ratio Mg0.22B2 are prepared by oxidizing with I2 and delaminating from MgB2. The flakes have Mg atom deintercalation rate of 78% while maintaining the hexagonal structure of boron.