Assessment of Reaction Parameters in the Polymeric Carbon Nitride Thermal Synthesis and the Influence in Photocatalytic Hydrogen Production

Abstract

In this work, the reaction parameters for polymeric carbon nitride synthesis by thermal polycondensation were assessed, such as type of precursor, heating rate and time of thermal treatment, in order to obtain crystalline materials with high photocatalytic performance. All synthesized materials were tested as photocatalysts in hydrogen production using ethylenediaminetetraacetic acid (EDTA) as a sacrificial reactant under visible light irradiation (λ ≥ 420 nm). The synthesis condition capable to obtain the material that reached the best performance in photocatalytic hydrogen production was using thiourea as the precursor, due to the band gap narrowing and charge recombination suppression; an intermediate heating rate (5 ºC min-1) and a longer thermal treatment time (6 h) that yielded a better crystalline solid. The combination of these effects led the S-doped polymeric carbon nitride (SPCN4 sample) to a higher photocatalytic activity, reaching the maximum hydrogen production rate of 214.75 μmol g-1 h-1 .

Sugars induced exfoliation of porous graphitic carbon nitride for efficient hydrogen evolution in photocatalytic water-splitting reaction

“…Specifically, the peak centered at 466 nm is associated with the transition from π* to π, while the peak centered at 500 nm corresponds to the transition from π* to the conduction band with long-pair electrons 35 . The fundamental structure of graphitic carbon nitride consists of tri-s-triazine ring units connected by nitrogen atoms, forming a conjugated polymeric network 36 . The optical properties of carbon-based materials with the disorder are governed by the π and π* antibonding states within the UV–visible energy range 36 .…”

“…The fundamental structure of graphitic carbon nitride consists of tri-s-triazine ring units connected by nitrogen atoms, forming a conjugated polymeric network 36 . The optical properties of carbon-based materials with the disorder are governed by the π and π* antibonding states within the UV–visible energy range 36 . The luminescence behavior of carbon nitride materials is influenced by the size of the sp 2 C–N structure, and the presence of long-pair electrons associated with the nitride 36 .…”

“…The optical properties of carbon-based materials with the disorder are governed by the π and π* antibonding states within the UV–visible energy range 36 . The luminescence behavior of carbon nitride materials is influenced by the size of the sp 2 C–N structure, and the presence of long-pair electrons associated with the nitride 36 . Furthermore, the formation of the long-pair state arises from the non-hybridization of the long-pair electrons with carbon, leading to the sp 2 C–N π valance band 36 .…”

Sugars induced exfoliation of porous graphitic carbon nitride for efficient hydrogen evolution in photocatalytic water-splitting reaction

“…Speci cally, the peak centered at 466 nm is associated with the transition from π* to π, while the peak centered at 500 nm corresponds to the transition from π* to the conduction band with long-pair electrons [32]. The fundamental structure of graphitic carbon nitride consists of tri-s-triazine ring units connected by nitrogen atoms, forming a conjugated polymeric network [33]. The optical properties of carbon-based materials with the disorder are governed by the π and π* antibonding states within the UV-visible energy range [33].…”

“…The fundamental structure of graphitic carbon nitride consists of tri-s-triazine ring units connected by nitrogen atoms, forming a conjugated polymeric network [33]. The optical properties of carbon-based materials with the disorder are governed by the π and π* antibonding states within the UV-visible energy range [33].…”