Preparation of graphite-like carbon nitride nanoflake film with strong fluorescent and electrochemiluminescent activity

Abstract

The preparation, characterization, fluorescence (FL) and electrochemiluminescence (ECL) of graphite-like carbon nitride nanoflake particles (g-C₃N₄ NFPs) and nanoflake films (g-C₃N₄ NFFs) have been reported. Highly water-dispersible g-C₃N₄ NFPs with a height of ∼5 to 35 nm and a lateral dimension of ∼40 to 220 nm have been extracted from bulk g-C₃N₄ materials by chemical oxidation. New, stable and defined g-C₃N₄ NFFs can be easily obtained by drying NFPs on certain hydrophilic substrates such as glass or electrode surfaces. Both g-C₃N₄ NFPs and g-C₃N₄ NFFs have good FL activities, i.e. they can give strong blue light (435 nm) emission under UV light (365 nm) excitation. The as-prepared g-C₃N₄ NFFs on a glassy carbon electrode exhibit strong non-surface state ECL activity in the presence of reductive–oxidative coreactants, including dissolved oxygen (O₂), hydrogen peroxide (H₂O₂) and peroxydisulfate (S₂O₈²⁻) and give rise to blue light emission (435 nm), which is the same as the wavelength of FL. The non-surface state ECL mechanisms of the g-C₃N₄ NFF–coreactant systems have been studied and discussed in detail.