Synthesis of N-doped graphene quantum dots from bulk N-doped carbon nanofiber film for fluorescence detection of Fe³⁺ and ascorbic acid

Abstract

Nitrogen doped graphene quantum dots (N-GQDs) have attracted much attention because of their superior electronic and optical properties. The preparation of N-GQDs can be usually performed via a top-down method using vairous nanocarbon as raw materials. However, most carbon materials are powder, which increases the difficulty of separating quantum dots from the reaction solution. Herein, we verified a feasibility of N-GQDs preparation with a bulk carbon film composed of N-doped carbon nanofibers as raw mateial via an acid vapor cutting approach (only 1 ml nitric acid was used in the method). The synthesis method effectively voids a tedious separation process. And the as-prepared N-GQDs exhibit good dispersion, high photostability and blue-green fluorescence. Subsequently, fluorescence experiments confirmed the fluorescence of N-GQDs was quenched selectively by Fe³⁺ via the unique coordination interaction between them and recovered with the addition of AA. Based on the quenching (off) and recovering (on) processes, fluorescent sensor for Fe³⁺ and OFF-ON fluorescent sensor for AA were fabricated, showing good selectivity and wide linear range. Finally, the constructed sensors were successfully applied for Fe³⁺ and AA detection in real samples such as tap water and human urine.

Keywords:

• N-doped graphene quantum dots
• bulk N-doped carbon nanofiber film
• fluorescent sensor
• Fe³⁺
• ascorbic acid

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors acknowledge the financial support from the project of Hebei Province Natural and Scientific Foundation (B2017101022, B2017101018), the project of the top talent (BJ2018208) and young foundation (QN2017408) of Hebei Province Educational Bureau. Science and technology project of Chengde High-tech Industrial Development Zone (HZLC2018005).