From Melamine‐Cyanuric Acid Supramolecular Aggregates to Carbon Nitride Hollow Spheres

TLDR

Graphitic carbon nitride is a promising metal‑free catalyst whose performance can be tuned by texture, optical, and electronic modifications, yet simultaneous optimization of these properties remains unachieved. The study reports a facile synthesis of mesoporous g‑CN via molecular cooperative assembly of triazine molecules. Flower‑like melamine‑cyanuric acid aggregates precipitated from DMSO are thermally polycondensed at 550 °C under nitrogen to form mesoporous hollow spheres of triazine‑based g‑CN nanosheets. These hollow spheres exhibit stronger optical absorption, a 0.16‑eV wider bandgap, twice the charge‑carrier lifetime, and enable a tenfold acceleration of rhodamine B photodegradation.

Abstract

Abstract Graphitic carbon nitride (g‐CN) is a promising heterogeneous metal‐free catalyst for organic photosynthesis, solar energy conversion, and photodegradation of pollutants. Its catalytic performance is easily adjustable by modifying texture, optical, and electronic properties via nanocasting, doping, and copolymerization. However, simultaneous optimization has yet to be achieved. Here, a facile synthesis of mesoporous g‐CN using molecular cooperative assembly between triazine molecules is reported. Flower‐like, layered spherical aggregates of melamine cyanuric acid complex (MCA) are formed by precipitation from equimolecular mixtures in dimethyl sulfoxide (DMSO). Thermal polycondensation of MCA under nitrogen at 550 °C produces mesoporous hollow spheres comprised of tri‐ s ‐triazine based g‐CN nanosheets (MCA‐CN) with the composition of C 3 N 4.14 H 1.98 . The layered structure succeeded from MCA induces stronger optical absorption, widens the bandgap by 0.16 eV, and increases the lifetime of photoexcited charge carriers by twice compared to that of the bulk g‐CN, while the chemical structure remains similar to that of the bulk g‐CN. As a result of these simultaneous modifications, the photodegradation kinetics of rhodamine B on the catalyst surface can be improved by 10 times.