In situ formation of a Bi2MoO6/Bi2O3 p–n composite for enhanced photocatalytic activity and energy storage

• Bi 2 MoO 6 has been grown on a preformed Bi 2 O 3 particle to form p-n heterojunction. • The construction of p–n heterojunction improves charge transfer and electrochemical activity. • The BBM10 reveals a larger specific capacitance and improved rate capability. • The photocatalytic performance also significantly enhanced. Heterostructured materials composed of distinct semiconductors can generate built-in electric fields and provide additional active sites, thereby enhancing electron/ion transport and redox reactions for energy storage and photocatalytic applications. In this study, a novel strategy is proposed involving the growth of Bi 2 MoO 6 on preformed Bi 2 O 3 particles to construct a p–n Bi 2 O 3 /Bi 2 MoO 6 heterojunction. The established internal electrostatic field (EIEF) between p-type Bi 2 O 3 and n-type Bi 2 MoO 6 , in conjunction with oxygen vacancy-induced defects, facilitates charge transfer and enhances electrochemical activity. As a result, the energy-related applications of Bi 2 O 3 /Bi 2 MoO 6 , both as a supercapacitor and anode electrode, outperform those of pristine Bi 2 O 3 . The asymmetric supercapacitor (AS) based on Bi 2 O 3 /Bi 2 MoO 6 and activated carbon (AC) exhibits superior electrochemical performance, with an energy density of 31.0 Wh/kg and outstanding cycling durability, retaining 92.7% of its initial capacity after 10,000 cycles. The Bi 2 O 3 /Bi 2 MoO 6 heterojunction also demonstrates an increased photodegradation rate constant toward methylene blue (MB) under illumination with visible light, primarily due to its great charge transfer property