Construction of interfacial synergistic effect AlN/g-C3N4 2D/2D Z-type heterojunction for high-performance and stable visible-light photocatalytic removal of Rhodamine B and tetracycline

Abstract

This study featured the synthesis and characterization of a highly effective AlN/g-C3N4 composite photocatalyst using a combination of physical grinding and calcination methods. The composite material exhibited a unique two-dimensional/two-dimensional (2D/2D) structure, with flocculent g-C3N4 uniformly coated on the surface of AlN. A series of characterization techniques including FE-SEM, TEM, XRD, FT-IR and XPS committed the successful formation of the AlN/g-C3N4 heterostructure. The AlN/g-C3N4 composite demonstrates the improved catalytic efficiency compared to pure AlN, which can be evidenced by its exceptional photocatalytic degradation performance under visible-light irradiation. The AlN/g-C3N4 composite materials exhibited significant degradation of (RhB) and tetracycline (TC). Especially, the 20 % AlN/g-C3N4 component showed particularly remarkable adsorption and catalytic activity, with 98.4 % degradation of RhB solution in 25 min and 83.0 % degradation of TC solution in 60 min, with efficiencies about 3.9 and 6.8 times higher than that of pure g-C₃N4, attributed to its larger specific surface area and a smaller pore structure compared to pure g-C3N4. Moreover, the AlN/g-C3N4 heterojunction exhibited outstanding stability and reusability throughout four consecutive experimental cycles, highlighting its long-lasting and reliable performance. FT-IR analysis confirmed the structural stability of the composite material, and the free radical experiments revealed the dominant role of the holes (h+) free radical in the photocatalytic reaction. Additionally, UV–vis diffuse reflectance and Mott-Schottky tests supported the Z-type charge carrier transport route as the photocatalytic mechanism. Overall, the AlN/g-C3N4 heterostructure have shown great potential as a highly efficient photocatalyst for pollutant degradation, due to its unique structure, high specific surface area, and effective charge carrier separation, making it a promising material for diverse environmental applications.