Enhanced pyrocatalysis of the pyroelectric BiFeO₃/g-C₃N₄ heterostructure for dye decomposition driven by cold-hot temperature alternation

The BiFeO₃/g-C₃N₄ heterostructure, which is fabricated via a simple mixing-calcining method, benefits the significant enhancement of the pyrocatalytic performance. With the growth of g-C₃N₄ content in the heterostructure pyrocatalysts from 0 to 25%, the decomposition ratio of Rhodamine B (RhB) dye after 18 cold-hot temperature fluctuation (25-65 ℃) cycles increases at first and then decreases, reaching a maximum value of ~94.2% at 10% while that of the pure BiFeO₃ is ~67.7%. The enhanced dye decomposition may be due to the generation of the internal electric field which strengthens the separation of the positive and negative carriers and further accelerates their migrations. The intermediate products in the pyrocatalytic reaction also have been detected and confirmed, which proves the key role of the pyroelectric effect in realizing the dye decomposition using BiFeO₃/g-C₃N₄ heterostructure catalyst. The pyroelectric BiFeO₃/g-C₃N₄ heterostructure shows the potential application in pyrocatalytically degrading dye wastewater.