Design of Nd-SrTiO3/SrCO3@Ag2O Z-scheme heterojunction with the dual internal electric field for piezo-photocatalytic removal of pollutants

With the increasing severity of environmental pollution problems, developing efficient and low-cost pollution control technologies has become an urgent task. This study designed and prepared a novel Nd-SrTiO₃/SrCO₃@Ag₂O (Nd-SSTO/Ag₂O) dual internal electric field material for piezoelectric photocatalytic removal of pollutants from water. Under simulated sunlight irradiation, the material exhibited excellent photocatalytic activity. Among them, under single visible light irradiation and single ultrasound vibration, the degradation rate of RhB by 2.5 % Nd-SSTO/Ag₂O-0.2 only reached 22.4 % and 25.6 % in 1 h, respectively. However, when visible light and ultrasound vibration act simultaneously, the degradation rate of RhB by 2.5 % Nd-SSTO/Ag₂O-0.2 reached 95.1 % in 1 h with the reaction rate constants being 8.86 times and 1.64 times those of SSTO and Ag₂O respectively. Furthermore, after four cyclic experiments, the degradation efficiency of RhB by 2.5 % Nd-SSTO/Ag₂O-0.2 remained above 90 %. Additionally, ICP analysis revealed that the amount of catalyst elements released into the solution during the degradation process was extremely low, indicating that the prepared 2.5 % Nd-SSTO/Ag₂O-0.2 catalyst possesses good stability. Through Nd doping, the light absorption range of SSTO was extended from the ultraviolet region to the visible region. After inducing Ag₂O, a Nd-SSTO/Ag₂O Z-scheme heterojunction was formed with the dual internal electric field, which not only expanded the carrier transmission channel but also improved the photo-induced carrier separation, allowing more e^- and h⁺ to participate in the photocatalytic degradation reaction. Additionally, the piezoelectric characteristics of SrTiO₃ (STO) further accelerated the migration of e^--h⁺ pairs. This study opens up a new idea for the development and preparation of high-efficiency piezoelectric photocatalytic materials, and also provides a potential technical approach for environmental pollution control.