Fe3O4gC3N4复合催化剂增强芬顿光芬顿和类过氧化酶反应的活性及稳定性

Chinese Journal of Catalysis 38 (2017) 2110–2119 催化学报 2017年 第38卷 第12期 |   available at   journal homepage:   Article (Special Issue on Photocatalysis in China) Enhanced Fenton, photo‐Fenton and peroxidase‐like activity and stability over Fe3O4/g‐C3N4 nanocomposites Shafaq Sahar a, Akif Zeb a,b, Yanan Liu a, Naseeb Ullah a, Anwu Xu a,* a Division of Nanomaterials and Chemistry, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, Anhui, China b Institute of Environmental Sciences and Engineering (IESE), School of Civil and Environmental Engineering (SCEE), National University of Sciences and Technology (NUST), Sector H‐12, Islamabad, Pakistan ARTICLE INFO  ABSTRACT Article history: Received 10 October 2017 Accepted 30 October 2017 Published 5 December 2017  We prepared the Fe3O4/g‐C3N4 nanoparticles (NPs) through a simple electrostatic self‐assembly method with a 3:97 weight ratio to investigate their Fenton, photo‐Fenton and oxidative functional‐ities besides photocatalytic functionality. We observed an improvement of the Fenton and pho‐to‐Fenton activities of the Fe3O4/g‐C3N4 nanocomposites. This improvement was attributed to effi‐cient charge transfer between Fe3O4 and g‐C3N4 at the heterojunctions, inhibition of electron‐hole recombination, a high surface area, and stabilization of Fe3O4 against leaching by the hydrophobic g‐C3N4. The obtained NPs showed a higher degradation potential for rhodamine B (RhB) dye than those of Fe3O4 and g‐C3N4. As compared to photocatalysis, the efficiency of RhB degradation in the Fenton and photo‐Fenton reactions was increased by 20% and 90%, respectively. Additionally, the horseradish peroxidase (HRP) activity of the prepared nanomaterials was studied with 3,3,5,5‐tetramethylbenzidinedihydrochloride (TMB) as a substrate. Dopamine oxidation was also examined. Results indicate that Fe3O4/g‐C3N4 nanocomposites offers more efficient degradation of RhB dye in a photo‐Fenton system compared with regular photocatalytic degradation, which re‐quires a long time. Our study also confirmed that Fe3O4/g‐C3N4 nanocomposites can be used as a potential material for mimicking HRP owing to its high affinity for TMB. These findings suggest good potential for applications in biosensing and as a catalyst in oxidation reactions. © 2017, Dalian Institute of Chemical Physics, Chinese Academy of Sciences.Published by Elsevier B.V. All rights reserved.Keywords: Fe3O4/g‐C3N4 nanocomposites, Fenton reaction Dye degradation Peroxidase activity Horseradish peroxidase mimicking Dopamine oxidation  1. Introduction Graphitic carbon nitride (g‐C3N4) has been extensively in‐vestigated for its photocatalytic water splitting and catalytic abilities among its properties [1]. The structure of g‐C3N4 re‐sembles that of graphite and consists of multiple parallel layers of stacked tri‐s‐triazine units held together by van der Waals forces [2,3]. This stacking of tri‐s‐triazine units is responsible for the nanoflake‐like structure of carbon nitride and its large surface area. This material shows no solubility in most solvents such as water, alcohol, tetrahydrofuran (THF), diethyl ether, or toluene, which makes it an attractive photocatalyst material for degrading organic pollutants in the environment [4]. In com‐parison with other photocatalytic materials, carbon nitride is cheap, stable, and has low toxicity. Furthermore, g‐C3N4 can be easily‐prepared via a thermal treatment of melamine in an in‐* Corresponding author. Tel/Fax: +86‐551‐63602346; E‐mail: [e-mail] This work was supported by the National Natural Science Foundation of China (51572253, 21771171), Scientific Research Grant of Hefei Science Center of CAS (2015SRG‐HSC048), cooperation between NSFC and Netherlands Organization for Scientific Research (51561135011), and CAS‐TWAS Scholarship Program. DOI: 10.1016/S1872‐2067(17)62957‐7 | | Chin. J. Catal., Vol. 38, No. 12, December 2017 Shafaq Sahar et al. / Chinese Journal of Catalysis 38 (2017) 2110–2119 2111 ert atmosphere [5,6], and has a mid‐wide band gap of 2.7 eV [1]. Notably, nitrogen present in the structure of g‐C3N4 con‐tributes to the formation of a lone pair (LP) valence band, which is responsible for the electronic structure and properties of g‐C3N4 [7]. Many studies have been conducted on the photo‐catalytic properties of carbon nitride; however, investigations of the degradation of organic pollutants by this material are somewhat limited owing to the fast electron‐hole recombina‐tion [8–10]. As reported in previous studies, the band gap of g‐C3N4 can be tuned by reshaping the morphology of the mate‐rial, surface modifications or the separation of the holes and electrons [11]. The latter effect can be achieved by doping of g‐C3N4 with either metallic or non‐metallic ions and through t