物理化学学报2021，Vol.37Issue(6)：157-170,14.DOI:10.3866/PKU.WHXB202010030
全有机S型异质结PDI-Ala/S-C3N4光催化剂增强光催化性能
All Organic S-Scheme Heterojunction PDI-AlalS-C3N4 Photocatalyst with Enhanced Photocatalytic Performance
摘要
Abstract
Organic photocatalysts have attracted attention owing to their suitable redox band positions,low cost,high chemical stability,and good tunability of their framework and electronic structure.As a novel organic photocatalyst,PDI-Ala (N,N'-bis(propionic acid)-perylene-3,4,9,10-tetracarboxylic diimide) has strong visible-light response,low valence band position,and strong oxidation ability.However,the low photogenerated charge transfer rate and high carrier recombination rate limit its application.Due to the aromatic heterocyclic structure of g-C3N4 and large delocalized π bond in the planar structure of PDI-Ala,g-C3N4 and PDI-Ala can be tightly combined through π-π interactions and N—C bond.The band structure of sulfur-doped g-C3N4 (S-C3N4) matched well with PDI-Ala than that with g-C3N4.The electron delocalization effect,internal electric field,and newly formed chemical bond jointly promote the separation and migration of photogenerated carriers between PDI-Ala and S-C3N4.To this end,a novel step-scheme (S-scheme) heterojunction photocatalyst comprising organic semiconductor PDI-Ala and S-C3N4 was prepared by an in situ self-assembly strategy.Meanwhile,PDI-Ala was self-assembled by transverse hydrogen bonding and longitudinal π--π stacking.The crystal structure,morphology,valency,optical properties,stability,and energy band structure of the PDI-Ala/S-C3N4 photocatalysts were systematically analyzed and studied by various characterization methods such as X-ray diffraction,transmission electron microscopy,energy dispersive X-ray spectrometry,X-ray photoelectron spectroscopy,ultraviolet visible diffuse reflectance spectroscopy,electrochemical impedance spectroscopy,and Mott-Schottky curve.The work functions and interface coupling characteristics were determined using density functional theory.The photocatalytic activities of the synthesized photocatalyst for H2O2 production and the degradation of tetracycline (TC) and p-nitrophenol(PNP) under visible-light irradiation are discussed.The PDI-Ala/S-C3N4 S-scheme heterojunction with band matching and tight interface bonding accelerates the intermolecular electron transfer and broadens the visible-light response range of the heterojunction.In addition,in the processes of the PDI-Ala/S-C3N4 photocatalytic degradation reaction,a variety of active species (h+,·O2-,and H2O2) were produced and accumulated.Therefore,the PDI-Ala/S-C3N4 heterojunction exhibited enhanced photocatalytic performance in the degradation of TC,PNP,and H2O2 production.Under visible-light irradiation,the optimum 30％PDI-Ala/S-C3N4 removed 90％ of TC within 90 min.In addition,30％PDI-Ala/S-C3N4 displayed the highest H2O2 evolution rate of 28.3 μmol·h-1·g-1,which was 2.9 and 1.6 times higher than those of PDI-Ala and S-C3N4,respectively.These results reveal that the all organic photocatalyst comprising PDI-based supramolecular and S-C3N4 can be efficiently applied for the degradation of organic pollutants and production of H2O2.This work not only provides a novel strategy for the design of all organic S-scheme heterojunctions but also provides a new insight and reference for understanding the structure-activity relationship of heterostructure catalysts with effective interface bonding.关键词
可见光光催化/S型异质结/C3N4/π-π相互作用/H2O2Key words
Visible light photocatalysis/Step-scheme heterojunction/C3N4/π-πinteractions/H2O2分类
化学化工引用本文复制引用
李喜宝,刘积有,黄军同,何朝政,冯志军,陈智,万里鹰,邓芳..全有机S型异质结PDI-Ala/S-C3N4光催化剂增强光催化性能[J].物理化学学报,2021,37(6):157-170,14.基金项目
The project was supported by the National Natural Science Foundation of China (51962023,51772140,21603109),the Natural Science Foundation of Jiangxi Province,China (20192ACBL21047,20171ACB21033),the Henan Joint Fund of the National Natural Science Foundation of China (U1404216),the Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle (Nanchang Hangkong University) (ES202002077).国家自然科学基金(51962023,51772140,21603109),江西省自然科学基金(20192ACBL21047,20171ACB21033),国家自然科学基金河南联合基金(U1404216)和江西省持久性污染物控制与资源循环利用重点实验室开放基金(南昌航空大学)(ES202002077)资助 （51962023,51772140,21603109）
