Ag/polyaniline heterostructured nanosheets loaded with g-C3N4 nanoparticles for highly efficient photocatalytic hydrogen generation under visible light

Abstract

The design and integration of multiple active materials into hierarchical nanoarchitectures are essential for the creation of photocatalytic hydrogen evolution reaction systems. Here uniform Ag nanoparticles (NPs)/polyaniline (Ag/PANI) heterostructured nanosheets modified by g-C₃N₄ NPs are fabricated through a “green” liquid probe sonication route and hydrothermal synthesis for the first time. The results of photocatalytic experiments demonstrate that the g-C₃N₄–Ag/PANI hierarchical photocatalysts exhibit significantly enhanced photocatalytic activity for water splitting H₂ production under visible light irradiation. The amounts and size of g-C₃N₄ NPs in the composites have a remarkable effect on their photocatalytic activity. The optimal hydrogen evolution rate over g-C₃N₄–Ag/PANI with an apparent quantum efficiency (AQE) of 14.6% is 210.73 μmol h⁻¹ mg⁻¹, which is 96.7 times higher than that of Ag/PANI composites and 4.62 times better than that of g-C₃N₄ NPs. The nanoarchitectured nanosheets have significant structural advantages and can provide a large amount of reaction active sites and outstanding visible light utilization. In addition, the band structure difference and the surface plasmon resonance (SPR) of Ag NPs in ternary heterostructures can promote the spatial separation and transport efficiency of photogenerated charge carriers. These positive factors ultimately contribute to the superior photocatalytic activity for hydrogen production. Meanwhile, the photocatalyst exhibits high stability and reusability. This idea of composite design will be useful for the development of both hydrogen generation and multifunctional composite materials.