Practical room temperature formaldehyde sensing based on a combination of visible-light activation and dipole modification. Issue 42 (21st October 2021)

• Record Type: Journal Article
• Authors: Liang, Hongping; Guo, Lanpeng; Cao, Nengjie; Hu, Huiyun; Li, Hao; Frans de Rooij, Nicolaas; Umar, Ahmad; Algarni, Hamed; Wang, Yao; Zhou, Guofu
• Is Part Of: Journal of materials chemistry. Volume 9:Issue 42(2021)
• Page Start: 23955
• Page End: 23967
• Publication Date: 2021-10-21
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d1ta06346d
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : The rich oxygen vacancies and dipoles are beneficial for the formation of electrons and charge transfer of sensing system, respectively. HCHO sensing performances were enhanced by the combination of visible-light activation and dipole modification. Abstract : Implementing sensitive and fast ppb-level formaldehyde sensing at room temperature is still in extreme demand for practical indoor air quality monitoring. Herein, we developed a visible-light-sensitive and dipole-modified graphene-based nanocomposite ZnO x @ANS-rGO for ultrasensitive trace formaldehyde sensing. The rich oxygen vacancy zinc oxide (ZnO x ) nanoparticles on graphene nanosheets provide OH-groups and edge sorption sites to facilitate the activation of adsorbed oxygen. Moreover, the supramolecular assembled 5-aminonaphthalene-1-sulfonic acid-modified graphene (ANS-rGO) nanosheets with donor–π–acceptor dipole served as an excellent conduction platform to transport and collect photo-generated electrons. Based on the collaboration of rich ZnO x and ANS-rGO, the obtained sensor ZnO x @ANS-rGO-0.1 showed the highest response ( R a / R g = 1.58 to 1 ppm HCHO) among the MOS materials reported so far, and its limit of detection (LOD) can be as low as 5 ppb under 405 nm light illumination at RT. The outstanding efficiency and accuracy of the obtained gas sensor were confirmed by practical performance estimation in a 30 m 3 chamber. The selectivity, long-term stability, repeatability and humidity resistance of the obtained sensors at RT were also revealed. The sensing mechanism based on the combination of visible-light activation and dipole modification was analyzed by the O-XPS, PL, in situ ATR-FTIR and charge density difference calculation.