One-Pot Thermal Synthesis of g-C3N4/ZnO Composites for the Degradation of 5-Fluoruracil Cytostatic Drug under UV-LED Irradiation

Abstract

Graphitic carbon nitride (g-C3N4) was used to enhance the photocatalytic activity of ZnO nanoparticles for the degradation of 5-fluorouracil (5-FU) cytostatic drug under UV-LED irradiation. CN/ZnO composites were synthetized by an easy one-pot thermal method, varying the g-C3N4 loading, i.e., from 10 to 67 wt% and a post-thermal exfoliation in air. The physicochemical and optical properties of the materials were analyzed by several techniques. CN/ZnO composites showed a coral-like structure of spherical ZnO wurtzite particles on the g-C3N4 structure. In general, the synergism and heterojunction interface between both phases allowed the enhancement of the mesoporosity, light absorption ability, and the aromaticity of the corresponding composites. Moreover, the photocatalytic activity of the CN/ZnO composites was increased with the addition of g-C3N4 in comparison with pristine ZnO. The highest activity was found for the composite containing 25 wt% of g-C3N4 (i.e., CN25/ZnO), reaching the total degradation of 5-FU and a mineralization of 48% at 180 min, as well as a good photostability during four reuse cycles. Experiments with different pH solutions and scavengers allowed for the assessment of the reactive oxygen species (ROS) involved in the 5-FU degradation pathway, with radicals and non-radical species as the main responsible active species. Furthermore, a tentative photocatalytic mechanism was proposed for CN/ZnO composites.

One-Step Fabrication of the ZnO/g-C3N4 Composite for Visible Light-Responsive Photocatalytic Degradation of Bisphenol E in Aqueous Solution

“…Figure a shows the Kubelka-Munk function of the UV–vis DRS of the prepared ZnO, g-C 3 N 4 , and the ZnO/g-C 3 N 4 composite after the degradation reaction of BPE. It was observed that the prepared ZnO and g-C 3 N 4 had the absorption edge at about 390 and 430 nm, respectively. Moreover, the absorption edge of the prepared ZnO/g-C 3 N 4 composite was significantly red-shifted to a higher wavelength compared to both pure ZnO and g-C 3 N 4 .…”

“…Recently, g-C 3 N 4 has received great attention as an interesting photocatalyst for wastewater detoxification, hydrogen production, and photoreduction of CO 2 under visible light irradiation. Pure g-C 3 N 4 possesses a moderate band gap of ∼2.7 eV, which enables it to be excited by visible light up to 460 nm. − Furthermore, metal-free g-C 3 N 4 has several features required for photocatalysis reactions, such as a π-conjugated electronic structure, layered crystal structure, low cost, nontoxic nature, high chemical and thermal stability, high electron conductivity, and facile fabrication. ,− However, the photocatalytic efficiency of g-C 3 N 4 is greatly reduced because of the low quantum efficiency and fast recombination rate of the photogenerated electron–hole pairs. , Hence, to reduce the drawbacks of g-C 3 N 4 , several methods such as coupling with metal organic frameworks, covalent organic frameworks and other semiconductors (metal oxides and metal sulfides), doping with elements, and monitoring its structure and morphology have been proposed. ,− For instance, Kuila et al reported the synthesis of cerium ion-adsorbed g-C 3 N 4 for enhancing the photocatalytic degradation of methylene blue dye under sunlight irradiation . de Sousa et al prepared a ternary photocatalyst of ZnO/g-C 3 N 4 /carbon xerogel, which was used in efficient photocatalytic degradation of 4-chlorophenol under visible light irradiation .…”

Tunable Carrier Transfer of Polymeric Carbon Nitride with Charge-Conducting CoV2O6∙2H2O for Photocatalytic O2 Evolution

“…Both TEM elemental mapping ( Figure 2 e) and EDX analysis (Figure S2) of CoVO/PCN showed Co, V, O, and C, N elements visually belonging to CoVO and PCN. The coexistence of CoVO lattices and amorphous PCN observed in Figure 2 c,d illustrate that a tight heterojunction between CoVO and PCN was formed in the hybrid [ 38 ]. Additionally, the BET-specific surface areas of PCN and 3 wt % CoVO/PCN were 62 and 56 m 2 g −1 (Figure S1b) , respectively.…”

“…The Co 2p spectrum in Figure 3 b is described as two peaks of Co 2P 2/1 at 797.3 eV and Co 2P 2/3 at 781.1 eV, with additional satellite peaks situated at 787.1 eV and 803.5 eV [ 36 ]. The V 2p spectrum in Figure 3 c is located at 524.6 eV and 517.2 eV corresponding to the V 2p 1/2 and V 2p 3/2 [ 36 , 38 ]. The O 1s spectrum is shown in Figure 3 d and can be split into three peaks at binding energies of 530.3 and 532.0 eV, which were attributed to the Co–O bond and the oxygen in the surface hydroxyl groups (C–OH) [ 28 ].…”

Synthesis of Nanocomposites and Catalysis Applications

“…In the case of the utilization of methane formed during the extraction of natural resources, the process of the deactivation of catalysts occurring under the conditions of a deep oxidation reaction based on La-Ca-Mn-Co perovskites was considered in [ 8 ] by the in situ XRD method. In [ 9 ], a g-C 3 N 4 /ZnO nanocomposite was used for the degradation of 5-fluoruracil cytostatic drug under UV–LED irradiation.…”