In situ construction of Z-scheme g-C3N4/Mg1.1Al0.3Fe0.2O1.7 nanorod heterostructures with high N2 photofixation ability under visible light

Abstract

By tuning the metal ratio, a Z-scheme g-C₃N₄/MgAlFeO nanorod composite was prepared in situ. The nitrogen photofixation performance under visible light was tested to evaluate the performance of the prepared catalysts. Strong electronic coupling, as evidenced by the XPS, PL and EIS results, exists between the two components in the g-C₃N₄/Mg_1.1Al_0.3Fe_0.2O_1.7 heterojunction photocatalysts, leading to a more effective separation of photogenerated electron–hole pairs and faster interfacial charge transfer, causing the higher activity and stability for N₂ photofixation. Neat MgAlFeO shows almost no N₂ photofixation activity. However, with the MgAlFeO mass percentage of 23.6%, the as-prepared heterojunction photocatalyst exhibits the highest NH₄⁺ generation rate under visible light, which is 3.5-fold greater than that of individual g-C₃N₄. A possible Z-scheme mechanism is proposed.