2D materials-based hybrid films for rhodamine B removal and SERS detection

abstract

Growing concerns among consumers and regulatory authorities regarding food safety have highlighted the need for effective detection and removal of hazardous substances. Rhodamine B (RhB), an illegal food dye with known genotoxic and carcinogenic properties, poses a significant threat to food safety and human health. In this study, we report for the first time the fabrication of multifunctional hybrid films composed of graphene oxide (GO) and molybdenum disulfide (MoS2) nanosheets for the dual purpose of RhB removal and surface-enhanced Raman scattering (SERS) detection. Hybrid films were engineered by varying the relative concentrations and compositions of the GO and MoS2. Structural analysis revealed that the increased MoS2 content in the hybrid films resulted in the formation of two distinct regions, a dense MoS2-rich bottom layer and a GO-enriched upper layer. Adsorption studies showed that the RhB removal efficiency increased with MoS2 content, achieving up to 99.9 % removal with films composed entirely of MoS2 (100 wt%). SERS analysis revealed a relationship between the MoS2 and GO content in the hybrid films and the Raman signal intensity of RhB. These outcomes can be attributed to the differences in the molecular interactions between RhB and the individual film components of the sensors. To balance the high adsorption efficiency with sensitive detection, hybrid films containing 75 and 100 wt% MoS2 (GO/MoS2_25/75, GO/MoS2_0/100, respectively) were selected for further validation. The proofof-concept was demonstrated using RhB-spiked sweet pepper powder, where the GO/MoS2_0/100 film achieved a detection limit of 0.01 wt% (100 ppm), and the GO/MoS2_25/75 film detected as low as 0.1 wt% (1000 ppm). In addition, RhB was detected in complex water samples, namely wastewater, mineral water, tap water, and Aveiro Estuary water, using the GO/MoS2_0/100 film, with a detection limit of 100 nM for the latter. Overall, this study introduces a new class of multifunctional 2D-material-based hybrid films that merge adsorption and SERS sensing capabilities within a single architecture, offering a technologically meaningful and simple approach for ultrasensitive, on-site monitoring and removal of illicit food dyes and related contaminants.

keywords

ENHANCED RAMAN-SCATTERING; GRAPHENE OXIDE; FOOD SAFETY; CHILI-POWDER; MOS2; MOLECULES; SENSORS; SIGNAL

subject category

Chemistry; Materials Science

authors

de Sousa, BP; Amaral, L; Daniel-da-Silva, AL; Trindade, T; Gonçalves, G; Fateixa, S

Groups

G1 - Porous Materials and Nanosystems

Projects

CICECO - Aveiro Institute of Materials (UIDB/50011/2020)

CICECO - Aveiro Institute of Materials (UIDP/50011/2020)

Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)

Collaboratory for Emerging Technologies, CoLab (EMERGING TECHNOLOGIES)

acknowledgements

This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 (DOI 10.54499/UIDB/50011/2020) , UIDP/50011/2020 (DOI 10.54499/UIDP/50011/2020) & LA/P/0006/2020 (DOI 10.54499/LA/P/0006/2020) . This work is funded by national funds through FCT, I.P., under UID/00481 - TEMA. GG thanks to the FCT for the financial support to the project CarboNCT 2022.03596.PTDC (DOI: 10.54499/2022.03596.PTDC) SF thanks FCT for her research contract (REF- 069-88-ARH-2018) , which is funded by National funds (OE) through FCT, I. P., in the scope of the framework contract foreseen in numbers 4, 5, and 6 of article 23 of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. BPdS and LOA thank FCT for their PhD grants (2024.02680.BD and BD/151138/2021) , respectively. ALD-d-S acknowledges FCT for funding (CEECIND/03075/2018/CP1559/CT0020; DOI 10.54499/CEECIND/03075/20 18/CP1559/CT0020) .