Reinforced Photogenerated Electrons in Few-Layer C₃N₅ for Enhanced Catalytic NO Oxidation and CO₂ Reduction

Abstract

Two-dimensional (2D) polymer carbon nitrides are cutting-edge environment-friendly photocatalysts relying on their extraordinary properties of cost-effectiveness, low toxicity, visible-light response, and chemical stability. Here, we report few-layer C3N5 with a thickness of around 1.2 nm as a case study, whose photogenerated carriers’ dynamics achieve a significant increase proven by the transient diffuse reflectance spectra. In addition, few-layer C3N5 changes to mainly exhibit the behavior of photogenerated electrons in comparison to bulk C3N5, whose lifetime extends 3.25-fold and is even 3.72-fold of that for g-C3N4. Density functional theory calculations further verify the superior adsorption and activation of small molecules of NO, O2, and CO2 over few-layer C3N5. The abovementioned unique intrinsic properties endow few-layer C3N5 with a significantly enhanced photocatalytic capability in air NO oxidation and CO2 reduction with respect to bulk C3N5 and traditional C3N4. This work may help in developing efficient 2D metal-free catalysts for photocatalytic applications.

Template-Assisted Assembly of DPP-TTT over a Hydrophilic Liquid Subphase toward Enhanced Charge Transport in Organic Field-Effect Transistors

“…This peak corresponds to the repeat unit of the triazole. Thus, comparing with reported literature, , the XRD pattern indicates the successful formation of bulk C 3 N 5 .…”

Graphitic carbon nitride with the pyridinic N substituted by Al and Si as efficient photocatalysts for CO2 reduction

“…The initial step of the CO 2 RR is generally considered to be a difficult step with a high barrier in the literature. By inspecting the reaction barrier of this initial step on the g-C 3 N 4 doped with elements possessing weak metallicity (B, O, P, S, As, Se) and elements possessing strong metallicity (Al, Si, Ga, Ge), together with the barrier in the second reduction step on the Se-doped g-C 3 N 4 for additional verification, we generalize some important rules which are valuable for designing CO 2 RR catalysts based on g-C 3 N 4 and other metal-free materials including C 3 N 5 , 70,71 graphdiyne, 72 covalent organic frameworks, 73,74 conjugated microporous polymers, 75,76 etc. First, doping g-C 3 N 4 with weak-metallic elements is not an effective strategy to make the CO 2 RR run efficiently under ambient conditions, as the barrier of the initial step is still higher than 1.36 eV, while this barrier can be substantially lowered to no more than 0.85 eV by doping strong-metallic elements.…”

Isotype heterojunction: tuning the heptazine/triazine phase of crystalline nitrogen-rich C3N5 towards multifunctional photocatalytic applications

“…31 As such, the emergence of a carbon nitride allotrope represents a new paradigm of nanoengineering through chemical composition tuning. C 3 N 5 has shown a remarkable performance in photo-and electrocatalytic CO 2 reduction, 32,33 hydrogen evolution, 31,34 and other environmental applications. 35,36 The typical bulk condensation of N-rich precursors (i.e.…”