Novel Nd 3+ -doped β -Bi 2 O 3 /Bi 2 O 2 CO 3 composite nanoplates have been synthesized via a facile phase transformation route. The products generated in the phase transformation process of Nd 3+ -doped Bi 2 O 2 CO 3 crystals were analyzed by a series of physicochemical techniques, e.g., TG-DTG, BET, XRD, SEM, TEM, FT-IR, and UV–vis DRS. The analysis results revealed that when the calcination temperature increased to 300℃, a phase transformation occurred (Bi 2 O 2 CO 3  → Bi 2 O 3 ). However, the doping of Nd 3+ could restrain the conversion of β -Bi 2 O 3 to α -Bi 2 O 3 and promote the stability of β -Bi 2 O 3 crystal phase during the cooling process. The obtained Nd 3+ / β -Bi 2 O 3 /Bi 2 O 2 CO 3 composite nanoplates possess superior visible light photocatalytic performance in the decomposition of phenols (phenol, 2,4-dichlorophenol, bisphenol A, 4-nitrophenol) and acid orange II. The intimate β -Bi 2 O 3 /Bi 2 O 2 CO 3 heterojunction largely boosted the separation of photo-generated electrons and holes. Moreover, the doped Nd 3+ could also participate in the capture of electrons. Thus, more photo-generated electrons and holes are available to participate in the decomposition of pollutants. Graphical abstract The Nd 3+ doped β -Bi 2 O 3 /Bi 2 O 2 CO 3 composite nanosheets synthesized via a facile phase transformation route display superior visible light photocatalytic performance for phenols (phenol, 2,4-dichlorophenol, bisphenol A, 4-nitrophenol) and dye mineralization.