Preparation and Photocatalytic Degradation Performance of Amine-Rich Carbon Nitride with Structural Modulation of the Precursor

Abstract

The photocatalytic performance of graphitic phase carbon nitride (g-C3N4) is strongly influenced by its own microstructure as well as the precursor structure that causes the microstructure changes. In this paper, a composite precursor of sodium chloride and cyanamide (NaCl/CA-2) was obtained by freeze-drying, which possess an aggregated state different from that of the non-freeze-drying method. This new aggregation state with the introduction of sodium ions into the cyanamide lattice results in a higher activation energy of NaCl/CA-2 in the thermal polycondensation process of the molten salt-assisted preparation of g-C3N4, which prevented the condensation of two cyanamides to one dicyandiamide, ultimately obtaining FD-CN with an amino-rich structure. The nitrogen atoms on the amino group can provide the photocatalyst with more unpaired electrons that can participate in the photoexcitation process, further improving its electron–hole separation ability and charge transfer efficiency, thus effectively enhancing its photocatalytic activity. Compared to the original g-C3N4, the photocatalytic activity of FD-CN for the degradation of methylene blue increased 2.19 times.

Boosted Photocatalytic Degradation of Atrazine Using Oxygen-Modified g-C3N4: Investigation of the Reactive Oxygen Species Interconversion

“…Its advantages include inexpensiveness, nontoxicity, high stability, and being easy to synthesize. , The appropriate position of its conduction band (CB) and valence band (VB), along with its capability to adsorb molecular oxygen, has attracted significant interest in the field of molecular oxygen activation . Nevertheless, pristine g-C 3 N 4 has limited ability to activate molecular oxygen due to its intrinsic small specific surface area and high recombination rate of photoinduced charge carriers. , To overcome these limitations, various modification methods such as heterostructure construction, noble metal loading, and element doping have been employed to enhance their capacity for molecular oxygen activation. Oxygen doping is a notable example that has exhibited a remarkable capability to enhance the activation of molecular oxygen and improve pollutant removal efficiency in wastewater treatment. , This enhancement can be ascribed to the incorporation of oxygen atoms into the lattice structure of g-C 3 N 4 , leading to modifications in the electronic band structure, an increase in available surface active sites, and the facilitation of photoinduced charge carrier separation.…”