An Innovative Anion Regulation Strategy for Energy Bands of Semiconductors: A Case from Bi2O3 to Bi2O(OH)2SO4

How to develop a new, efficient photo catalyst is still a big challenge to us. A suitable band gap is the key for light absorption of semiconductor. Herein, an innovative anion intercalation strategy is, for the first time, developed to regulate the energy band of semiconductor. Typically, we introduce a layered sulfate compound (Bi2O(OH)2SO4) as a new photo catalyst, which has not been known before. Both partial density of states (PDOS) and total density of states (TDOS) have demonstrated that compared with Bi2O3 (2.85 eV), the band gap of Bi2O(OH)2SO4 has been widened to 4.18 eV by the intercalation of sulfate anion. Moreover, the band gap width of oxyacid salt compound is mainly predominated by the number of the outmost electrons (NOE) of central atom of anion. This study suggests that new photo catalysts can be developed by grouping anions with the existing oxides or sulfides.