Hybrid graphene nanoflakes for electrochemical sensing with multianalyte detection capability

• Published in: Diamond and related materials 2024-11, Vol.149, p.111511, Article 111511
• Main Authors: Banavath, Ramu, Nemala, Siva Sankar, Srivastava, Rohit, Rubino, Antonio, Capasso, Andrea, Bhargava, Parag
• Format: Article
• Language: English
• Subjects: Graphene and related materials; Hydrogen peroxide, ascorbic acid, and dopamine; Liquid phase exfoliation; Solid state sensors; Sustainable processing
• ISSN: 0925-9635
• DOI: 10.1016/j.diamond.2024.111511

This work illustrates the production of highly electrochemically active graphene by liquid phase exfoliation technique for ultrasensitive electrochemical sensors. An airless high-pressure spray technique was designed to exfoliate bulk natural graphite into nm-scaled flakes (referred as HP50). Transmission electron microscopy, Raman and X-ray photoelectron spectroscopy studies reveal that the HP50 sample has a mixed structure composed of amorphous carbon and a few-layer graphene fraction with high amount of edge plane defects. The HP50 flakes are drop cast on glassy carbon electrodes to test the simultaneous and selective electrochemical detection of hydrogen peroxide, ascorbic acid, and dopamine. In cyclic voltammetry measurements, hydrogen peroxide reduces at −0.2 V vs Ag/AgCl (1 M), while ascorbic acid and dopamine oxidize at 0.1 V vs Ag/AgCl (1 M) and 0.3 V vs Ag/AgCl (1 M), respectively. Linear sweep voltammetry demonstrates high sensitivity (164, 739, and 3357 μA mM−1 cm−2) and low limit of detection (15, 1.7, and 2.1 μM) for the three analytes, respectively. Interference studies confirm a high sensitivity and selectivity towards the different chemical species. The HP50-based multianalyte sensors are also tested against different environmental and commercial samples, illustrating their viability in practical applications. [Display omitted] •Graphene-based flakes are produced by airless high-pressure spray exfoliation.•The hybrid flakes are made of amorphous carbon and few-layer graphene.•High-density edge-plane defects translates into high electrochemical activity.•As electrode material they allow simultaneous and selective electrochemical sensing.•Interference studies confirm high performance vs H2O2, ascorbic acid and dopamine.