A bismuth rich hollow Bi4O5Br2photocatalyst enables dramatic CO2reduction activity

The insufficient separation of photogenerated charge carriers and faint CO2capture remains the major obstacles for photocatalytic conversion of CO2into solar fuel. Rational design of semiconductor photocatalysts with unique structures may be promising to break this bottleneck. Herein, bismuth rich Bi4O5B2hollow microspheres are designed as a robust photocatalyst for efficient CO2reduction. Thanks to the bismuth rich strategy, the highly dispersed band structure and the elevated conduction band (CB) potential facilitate the charge transfer and photoreduction ability. Meanwhile, hollow structure provides the large specific area and creates a resonance in its interior to enhance the CO2adsorption and activation. Benefiting from the collaborative promotion effect, the local charge arrangement and electronic structure are tuned so as to an exceptional efficiency of photocatalytic CO2conversion into CO (3.16 μmol g−1 h−1) and CH4(0.5 μmol g−1 h−1) is attained over hollow Bi4O5Br2, which is superior to that of solid Bi4O5Br2and BiOBr, as well as other reported Bi-based photocatalysts. This work paves new opportunities for exploring high-efficiency CO2photoreduction catalysts.