Two novel visible-light-responsive bismuth oxychloride photocatalysts Bi2EuO4Cl and Bi2NdO4Cl have been successfully developed via a solid-state reaction route. Their crystal structures and optical properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), diffuse reflectance spectra (DRS), and photoluminescence (PL) spectra. Fascinatingly, both the compounds possess considerable optical absorption in a broad region ranging from UV light to visible light. The indirect-transition optical band gaps of Bi2EuO4Cl and Bi2NdO4Cl are estimated to be 2.21 and 1.89 eV, respectively. For the first time, their photocatalytic activities were determined by photodecomposition of methylene blue (MB) in aqueous solution under visible light (λ>420 nm). The results revealed that both Bi2EuO4Cl and Bi2NdO4Cl can be used as effective visible-light-driven photocatalysts. In addition, theoretical calculations on the electronic structure, orbital constitutions and optical absorption of Bi2NdO4Cl were also performed. These findings shed light on the exploration of new photocatalytic materials activated by visible light.

•Bi-based hydroxyl oxalate Bi(C2O4)OH was explored as a novel photocatalyst.•It was successfully synthesized via a facile aqueous precipitation route.•Bi(C2O4)OH can effectively degrade RhB under UV light irradiation.•Hydroxyl radicals (OH) are the main active species for RhB photodegradation.•Its electronic structure was calculated by density functional calculations.A novel Bi-based hydroxyl oxalate Bi(C2O4)OH has been successfully synthesized via a facile aqueous precipitation route, and its photocatalytic activity was investigated for the first time. The as-prepared Bi(C2O4)OH nanorods were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–vis diffuse reflectance spectra (DRS) and photoluminescence (PL) spectra. It possesses an indirect-transition optical band gap of 3.73 eV. The electronic structure, density of states as well as light absorption of Bi(C2O4)OH were studied by the first principle calculations. The photocatalytic performance of the samples was determined by photodegradation of Rhodamine B (RhB) in aqueous solution. The results revealed that RhB can be effectively decomposed by Bi(C2O4)OH, and the sample with reactant molar ratio of 1:2 exhibits the highest photocatalytic activity. The active species trapping experiments over Bi(C2O4)OH indicated that the hydroxyl radicals (OH) are the most important active species in the process of RhB photodegradation.A novel Bi-based hydroxyl oxalate Bi(C2O4)OH has been successfully synthesized via a facile aqueous precipitation route, and its photocatalytic activity was investigated for the first time.