The effect of indium doping on the hydrogen evolution performance of g-C3N4 based photocatalysts

Abstract

Doping graphitic carbon nitride (g-C₃N₄) with metal ions has been developed as a facile approach to improve its visible light photocatalytic performance towards hydrogen evolution via water splitting. In this work, a series of In³⁺ doped g-C₃N₄ (In-g-C₃N₄) photocatalysts were prepared via in situ thermal copolymerization by using a mixture of dicyanamide and InCl₃ as precursors. It was proposed, for the first time, that the In³⁺ ions were doped into g-C₃N₄ in a unique quasi-interlayer fashion, which contributed to tunable separation efficiency and migration ability of the photogenerated carriers by simply adjusting the amount of In³⁺ doping without changing the band edge of g-C₃N₄. The In-g-C₃N₄ photocatalyst doped with an optimal amount of indium ions, i.e., 2.18 wt%, exhibited a hydrogen evolution rate of 1.35 mmol h⁻¹ g⁻¹, 17 times that of pristine g-C₃N₄ (0.08 mmol h⁻¹ g⁻¹), attributed to the synergistically promoted separation and migration of the photogenerated charge carriers.