基于g-C3N4异质结复合材料光催化降解污染物的研究进展

Progress in Photocatalytic Degradation of Pollutants Based on g-C3N4 Heterogeneous Junction Composites

随着现代工业的迅速发展,向环境中排放的有机物及重金属污染物与日俱增,光催化降解法是一种清洁、高效、低成本的处理手段。作为新兴非金属可见光驱动催化剂的g-C3N4具有廉价易得、无毒无害等优点,但存在可见光响应范围较窄、光生电子-空穴对复合率较高等明显问题,导致量子产率低,光催化效率不高。研究发现,部分金属硫化物、金属氧化物以及三元化合物等不同类型的半导体能够与g-C3N4形成异质结构,通过调控半导体的形貌能够在不同程度上与g-C3N4构成良好的晶格匹配,这有利于电子在两种或多种半导体之间传输。通过构建异质结构能够有效地降低带隙宽度,拓宽光响应范围,减小光生电子-空穴复合率,提高光催化效率。本文分类讲述了近几年常用的基于g-C3N4的复合半导体材料,它们都不同程度地实现了电子与空穴对的良好分离,有效地消除了各类有机物及重金属的污染,是具有应用价值的光催化剂候选者。

With the rapid development of modern industry,more and more organic and heavy metal pollutants are discharged into the environment.Photocatalytic degradation is a clean,efficient and low-cost treatment method.g-C3N4,as an emerging catalyst driven by non-metallic visible light,has many advantages,such as cheap and easy to obtain,non-toxic and harmless.However,there are obvious problems,such as narrow response range of visible light,high photoelectron-hole recombination rate,resulting in low quantum yield and low photocatalytic efficiency.Studies have found that different types of semiconductors,such as partial metal sulfide,metal oxide and ternary compound,can form heterogeneous structures with g-C3N4.By regulating the morphology of semiconductors,they can form a good lattice match with g-C3N4 to different degrees,which is conducive to the transfer of electrons between two or more semiconductors.By constructing heterogeneous structures,the band gap width can be effectively reduced,the optical response range can be widened,the photoelectron-hole recombination rate can be reduced,and the photocatalytic efficiency can be improved.In this paper,the g-C3N4-based composite semiconductor materials commonly used in recent years are described.They all achieve good separation of electron and hole pair to varying degrees,and effectively eliminate the pollution of various organic compounds and heavy metals.Therefore,they are photocatalyst candidates with application value.