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Novel porous β-Bi 2 O 3 /Bi 2 O 2 CO 3 p-n heterostructures were synthesized by partially decomposing porous Bi 2 O 2 CO 3 at 300-375°C. The structures, morphologies, optical properties, and specific surface areas of the as-synthesized samples were characterized by means of thermogravimetry and differential scanning 10 calorimetry, X-ray diffraction, scanning electron microscopy, UV-Vis spectroscopy, and N 2 gas adsorption. Two types of dye, methyl orange (MO) and methylene blue (MB), were chosen as model organic pollutants to evaluate the photocatalytic activity of the as-synthesized samples. The porous β-Bi 2 O 3 /Bi 2 O 2 CO 3 p-n heterostructures exhibited much higher photocatalytic activity than β-Bi 2 O 3 and Bi 2 O 2 CO 3 and MO and MB could be completely degraded within 24 and 50 min, respectively. In addition, 15 phenol as a colorless organic pollutant was also chosen to further study the photocatalytic activity of Bi CO 3 heterostructures also showed much higher photocatalytic activity for the photodegradation of phenol than β-Bi 2 O 3 and Bi 2 O 2 CO 3 . The obtained results indicated that the formed p-n heterojunction in the porous β-Bi 2 O 3 /Bi 2 O 2 CO 3 composite significantly contributed to the improvement of electron-hole separation and the enhancement of 20 photocatalytic activity. The mechanisms for the enhanced photodegradation of selected organic pollutants over the β-Bi 2 O 3 /Bi 2 O 2 CO 3 composite are discussed in this study. 65 et al. [18] synthesized Ag/Bi 2 O 2 CO 3 microspheres with a significantly enhanced photocatalytic activity compared with bare Bi 2 O 2 CO 3 for the photodegradation of MO in aqueous solution under UV-vis light. Recently, much research work has focused CO 3 composite photocatalysts showed enhanced photocatalytic activities for degrading organic pollutants under visible light due to the p-n heterojunction.