NOx degradation ability of S-g-C3N4/MgAl-CLDH nanocomposite and its potential application in cement-based materials

Zhengxian Yang; Xiaoli Xiong; Xueyuan Yan; Shengyang Luo; Yong Zhang; Bruno Briseghella; Giuseppe Carlo Marano

doi:10.1039/d3ra04243j

NO_x degradation ability of S-g-C₃N₄/MgAl-CLDH nanocomposite and its potential application in cement-based materials

RSC Adv. 2023 Jul 18;13(31):21510-21520. doi: 10.1039/d3ra04243j. eCollection 2023 Jul 12.

Authors

Zhengxian Yang¹, Xiaoli Xiong¹, Xueyuan Yan¹, Shengyang Luo¹, Yong Zhang¹, Bruno Briseghella¹, Giuseppe Carlo Marano²

Affiliations

¹ Joint International Research Laboratory of Deterioration and Control of Costal and Marine Infrastructures and Materials, College of Civil Engineering, Fuzhou University Fuzhou 350108 China y.zhang@fzu.edu.cn.
² Department of Structural, Geotechnical and Building Engineering, Politecnico di Torino Corso Duca degli Abruzzi 24-10129 Torino Italy.

Abstract

In this study a new photocatalytic nanocomposite, S-g-C₃N₄/MgAl-CLDH, was synthesized and implemented into cement mortar by internal mixing or coating. The photocatalytic NO_x degradation efficiency of the S-g-C₃N₄/MgAl-CLDH and photocatalytic mortar was investigated. The NO_x degradation efficiency and photoluminescence spectra of S-g-C₃N₄/MgAl-CLDH after being immersed in the simulated concrete pore solution were evaluated to assess its chemical stability. The results show that compared with S-g-C₃N₄, the S-g-C₃N₄/MgAl-CLDH exhibits a narrower bandgap (2.45 eV), a lower photogenerated electron-hole pair recombination rate and a higher specific surface area (36.86 m² g^-1). After 21 min of visible light irradiation, the NO_x degradation rate of S-g-C₃N₄/MgAl-CLDH achieves 100% as compared to merely 81.5% of S-g-C₃N₄. After being submerged in simulated concrete pore solution, the S-g-C₃N₄/MgAl-CLDH exhibits only a slight decrease of 5% in degradation rate after 12 min of irradiation, confirming a good compatibility and stability in cement-based materials. The NO_x degradation ability of the internally mixed mortar is enhanced with an increase in the dosage of S-g-C₃N₄/MgAl-CLDH. For coated mortar, in contrast, a decline in NO_x degradation rate is observed after 5 layers of coating owing to the lower porosity of mortar after excessive coating.