Facile synthesis of the Z-scheme graphite-like carbon nitride/silver/silver phosphate nanocomposite for photocatalytic oxidative removal of nitric oxides under visible light

Guojun Li; Jia Guo; Yangyun Hu; Yanan Wang; Jianbo Wang; Shule Zhang; Qin Zhong

doi:10.1016/j.jcis.2020.12.063

Facile synthesis of the Z-scheme graphite-like carbon nitride/silver/silver phosphate nanocomposite for photocatalytic oxidative removal of nitric oxides under visible light

J Colloid Interface Sci. 2021 Apr 15:588:110-121. doi: 10.1016/j.jcis.2020.12.063. Epub 2020 Dec 31.

Authors

Guojun Li¹, Jia Guo¹, Yangyun Hu¹, Yanan Wang¹, Jianbo Wang¹, Shule Zhang², Qin Zhong³

Affiliations

¹ School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094, PR China.
² School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094, PR China. Electronic address: shulezhang@163.com.
³ School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094, PR China. Electronic address: zq304@njust.edu.cn.

PMID: 33388577
DOI: 10.1016/j.jcis.2020.12.063

Abstract

In this study, a novel ternary Z-scheme Graphite-like Carbon Nitride (g-C₃N₄)/Silver (Ag)/Silver Phosphate (Ag₃PO₄) photocatalyst was designed and prepared using a two-step method (sodium chloride (NaCl) template-assisted strategy plus selective deposition). Its photocatalysts performance against removing 400 ppm of Nitric Oxides (NOx) was then investigated. We found 50 wt% g-C₃N₄/Ag/Ag₃PO₄(AP-CN 2:1) catalyst removes up to 74% of NO in 90 min under the illumination of visible light (>420 nm), which is respectively 3.5 and 1.8 times higher than using g-C₃N₄ or Ag₃PO₄, alone. This improved performance was attributed to the formation of Z-scheme g-C₃N₄/Ag/Ag₃PO₄ heterojunction, driven by the built-in electric field across the g-C₃N₄/Ag/Ag₃PO₄ interface. These separated the electron-hole but enhanced the original strong oxidation and reduction performance of related components. The superior performance is also attributed to the improved surface area, enhanced hydrophilicity (H₂O₂) and better visible-light-harvesting capability of the composite compound. More importantly, the AP-CN 2:1 sample maintained a NO removal rate of more than 73% even after four rounds of recycling. The photocatalytic oxidation removal mechanism was evaluated using the radical-capture experiments, electron spin resonance (ESR) and ion-exchange high-performance liquid chromatography (HPLC) analysis. The findings of this work offer a simple but effective design of a highly reactive and practical ternary Z-scheme heterojunction photocatalysts for the removal of toxic NO.

Keywords: 3D porous structure; Photocatalytic oxidation NO removal; Salt template; Z-scheme g-C(3)N(4)/Ag/Ag(3)PO(4).