Synthesis of Mn-doped ErFeO₃ with enhanced photo and vibration catalytic activities

In this paper, a series of ErFe_1−xMn_xO₃ (x = 0, 0.1, 0.3, 0.5) were readily prepared by the sol–gel method, with citric acid as the combustion agent. The powder gradually changes from the orthorhombic phase (ErFeO₃, space group Pbnm) to the hexagonal phase (ErFe_0.5Mn_0.5O₃, space group P6₃cm). Reduction in the optical band gap from 2.10 eV of ErFeO₃ to 1.69 eV of ErFe_0.5Mn_0.5O₃ is observed. Photocatalytic study on methylene blue (MB) by visible light irradiation showed that the photocatalytic activities are greatly enhanced for Mn-substituted ErFeO₃, due to the narrower band gap and smaller particle size. Interestingly, ErFe_0.5Mn_0.5O₃ also behaves complete degradation of MB within 120 min vibration, indicating the existence of piezo-electrochemical coupling. The possible photocatalytic and vibration catalytic mechanism of this system was also proposed. The results indicates that this system will be a good candidate for the decomposition of organic pollutant through utilizing both the natural vibration and solar energy.