Effects of oxygen vacancy and N-doping on the electronic and photocatalytic properties of Bi2MO6 (M=Mo, W)

The electronic properties of Bi2MO6 (M=Mo and W) are studied by using the first-principles calculations. It is attributed to its smaller electron effective mass that Bi2WO6 has higher photocatalytic activity than Bi2MoO6. The oxygen vacancy in Bi2MO6 serves as a trapping center of photogenerated electrons and thus is in favor of the photocatalytic efficiency. Nitrogen-doping induces localized structure distortion and thus improves the separation of photogenerated electron-hole pairs. Moreover, band gaps decrease obviously with doping concentration increasing, therefore the photoabsorption edges will give rise to a redshift in Bi2MO6.