Fabrication of protonated g-C3N4 nanosheets as promising proton conductive materials

A top-down design for easy gram scale synthesis of melem nano rectangular prisms with improved surface area

An unprecedented top-down design for the preparation of melem by 1 h stirring of melamine-based g-C₃N₄ in 80 °C concentrated sulfuric acid (95-98%) was discovered. The melem product was formed selectively as a monomer on the gram scale without the need for controlled conditions, inert atmosphere, and a special purification technique. The as-prepared air-stable melem showed a distinctive nano rectangular prism morphology that possesses a larger surface area than the melems achieved by traditional bottom-up designs making it a promising candidate for catalysis and adsorption processes.

4-Nitrophenol Efficient Photoreduction from Exfoliated and Protonated Phenyl-Doped Graphitic Carbon Nitride Nanosheets

The photoreduction of 4-nitrophenol to 4-aminophenol by means of protonated and exfoliated phenyl-doped carbon nitride is reported. Although carbon nitride-based materials have been recognized as efficient photocatalysts, the photoreduction of 4-nitrophenol to 4-aminophenol is not allowed because of the high recombination rate of the photogenerated electron–hole pairs. In this paper, we show the morphology effects on the photoactivity in phenyl-doped carbon nitride. Structural (TEM, XRD, Raman) and optical characterization (absorption, photoluminescence) of the protonated and exfoliated phenyl-doped carbon nitride (hereafter pePhCN) is reported. The increased photocatalytic efficiency, with respect to the bulk material, is underlined by the calculation of the kinetic constant of the photoreduction process (2.78 × 10⁻¹ min⁻¹ and 3.54 × 10⁻³ min⁻¹) for pePhCN and bulk PhCN, respectively. Finally, the detailed mechanism of the photoreduction process of 4-nitrophenol to 4-aminophenol by modified phenyl carbon nitride is proposed.

Etching-induced highly porous polymeric carbon nitride with enhanced photocatalytic hydrogen evolution

Photocatalytic catalysts with a large specific surface area generally can not only supply more active sites but also facilitate the surface charge separation process. Here, we present a facile method to synthesize highly porous polymeric carbon nitride by an acid etching process. Benefitting from the porous structure and enlarged specific surface area, CN-0.25H reveals an enhanced photocatalytic hydrogen evolution rate. Experimental and computational results suggest that the improved surface charge separation process mainly accounts for the enhanced photocatalytic activity, illustrating the importance of the surface area for a CN photocatalyst.

Synergetic polarization effect of protonation and Fe-doping on g-C3N4 with enhanced photocatalytic activity

The local polarization electric field resulting from protonation and Fe-doping in g-C3N4 can be formed, thus highly facilitating the separation and transport of charge carriers and boosting the photocatalytic activity.

Enhanced reduction and oxidation capability over the CeO2/g-C3N4 hybrid through surface carboxylation: performance and mechanism

The charge separation efficiency of the CeO₂/g-C₃N₄ heterojunction was greatly enhanced through surface carboxylation of the g-C₃N₄ substrate.