In situ construction of η-Fe2O3/g-C3N4 Z-scheme heterojunction on nickel foam with efficient interfacial charge transport for enhanced photodegradation of Rhodamine B

Abstract

The design of efficient, low cost and recyclable photocatalyst is of great significance for disposing organic wastewater. In this work, η-Fe₂O₃/g-C₃N₄ heterostructure was constructed by in-situ cyclic voltammetry codeposition and calcination on nickel foam (NF). The microstructural and morphological characterization of the sample confirmed that spherical η-Fe₂O₃/g-C₃N₄ nanocomposites were co-deposited on three-dimensional porous NF to form Fe₂O₃/g-C₃N₄/NF photoelectrode under 50 cycles of 50 mV/s electric field. The removal rate of as-prepared η-Fe₂O₃/g-C₃N₄/NF photoelectrode for 10 mg·L⁻¹ Rhodamine B solution reaches 95.2 % in 1h, which is 5.6 times of g-C₃N₄/NF and 5.3 times of η-Fe₂O₃/NF, respectively. According to the electrochemical test results, the enhanced photocatalytic activity of η-Fe₂O₃/g-C₃N₄/NF was principally due to efficient photogenerated charge separation and transfer ability of the photoelectrode. The results of active species capture experiments indicate that superoxide radical, hydroxyl radical and hole almost equivalently participated in photodegradation of η-Fe₂O₃/g-C₃N₄/NF, and its possible photodegradation mechanism was proposed on the basis of Z-scheme charge transport path. The η-Fe₂O₃/g-C₃N₄/NF nanocomposites would be expected to become a promising photoelectrode for large-scale applications.