Facile assembly of a graphitic carbon nitride film at an air/water interface for photoelectrochemical NADH regeneration

Abstract

The development of a metal-free photoelectrode film is of great significance. Herein, graphitic carbon nitride (g-C₃N₄) nanosheets with a concentration of up to 36 mg mL⁻¹ were first obtained on a large scale using a wet ball-milling method. The obtained g-C₃N₄ nanosheets exhibit 6- and 8-times higher activity in terms of photocatalytic H₂ evolution and nicotinamide adenine dinucleotide (NADH) regeneration than bulk g-C₃N₄, respectively. Furthermore, a uniform g-C₃N₄ film electrode was fabricated via the interfacial self-assembly of nanosheets at the air/water interface, which can be transferred onto various substrates. By coupling with graphene nanosheets, a g-C₃N₄/graphene hybrid film electrode was assembled at the interface, showing improved photoelectrochemical coenzyme NADH regeneration efficiency. The photoelectrochemical system uses water as the electron donor, which avoids the drawback of using additional sacrificial agents. This work presents a novel and facile method to prepare high-quality g-C₃N₄ hybrid films, and also provides a sustainable route for renewable energy conversion and biocatalytic applications.