Synthesis Of G-C₃N₄/Alumina-Based Heterojunctions And Their Visible-Light Photocatalytic Activity

With the ever-increasing deterioration of environmental associated with economic growth, semiconductor photocatalysis technique has aroused much attention in degrading pollutants due to its potential utilization for clean, safe, and inexhaustible solar energy in the past few decades. The development of visible-light-driven photocatalysts is an essential prerequisite for practical application. Recently, graphite carbon nitride ?g-C₃N₄? has attacked great interest because of its inexpensive and relative narrow band gap of 2.70 eV. However, similar to other narrow-band-gap semiconductors, g-C₃N₄ also suffers from high recombination rate of photo-induced charge carriers and low quantum yield.In order to enhance the photocatalytic ability of pristine g-C₃N₄, many strategies have been employed.Among these methods, coupling g-C₃N₄ with other semiconductors is an effective measure.A new photocatalyst of MgAl₂O₄ nanopowders containing amorphous parts was developed by solution combustion method. Then,coupled g-C₃N₄ with amorphous MgAl₂O₄ via one-step combustion method.he photocatalytic performances of the composites are evaluated by the degradation of rhodamine B ?RhB? and methylene blue ?MB?.Based on the principle of amorphous MgAl₂O₄ Al-O bond length is shortened, and forbidden band width is reduced. Mesoporous amorphous ?-Al₂O₃ with high surface area ?159 m²/g? is prepared via precipitation method. The as-synthesized Al₂O₃ exhibits optical absorption ability in ultraviolet region. Al₂O₃ defect sites can transfer photo-generated electrons and is used as active component to be combined with g-C₃N₄ to form effective heterostructured photocatalysts. This heterojunction structure is confirmed by XRD, SEM, element map, TEM, HRTEM, FT-IR, and XPS measurements,The results confirmed its heterostructures. The photocatalytic performances of the composites are evaluated by the degradation of rhodamine B ?RhB?. The enhancement in activity of heteroj unctions is ascribed to their high specific surface areas, excellent adsorption abilities, and efficient transfer of photo-generated electrons from LUMO of g-C₃N₄ to defect sites of amorphous Al₂O₃.