Qian Yang,Wensong Lin,Zhichang Duan,Sen Xu,Junnan Chen,Xin Mai
In this work, g-C3N4/ZIF-8 heterojunction photocatalysts were synthesised by the process by which the metal-organic framework ZIF-8 nanoparticles were grown onto the g-C3N4 layer in situ. Bismuth element was doped into the as-prepared g-C3N4/ZIF-8 material and a new type of Bi@g-C3N4/ZIF-8 composite photocatalysts was manufactured, in which the doping element acts in adjusting the bandgap in the photocatalysts. The prepared photocatalysts were characterised by XRD, FESEM, TEM, FTIR, XPS, UV–VIS DRS, photoluminescence and photo-electrochemical experiments. The results show that the ZIF-8 nanoparticles grown in situ were well-formed onto the g-C3N4 layer, and bismuth was evenly doped into the gaps of the g-C3N4/ZIF-8 framework. The degradation rate of methylene blue by CNZ-1.5(Bi)-12, which was a photocatalyst composed of 12% Bi-doped with g-C3N4/ZIF-8 material (the mass ratio of g-C3N4: ZIF-8 = 1:1.5), reached 86.6% under visible light irradiation within 60 min. The free radical scavenging experiment and electron spin resonance spectroscopy showed that ∙OH was the main active substance. Bismuth doping into the photocatalytic system promotes the excitation of electrons from the valence band to the conduction band and provides a good channel for the transmission of photogenerated carriers as well. It is achieved that intensive visible light absorption, the enhanced separation efficiency of photogenerated carriers, and excellent thermal stability and high recyclability in the novel composite photocatalyst, owing to the synergistic effect of the introduced bismuth with the heterostructure of g-C3N4/ZIF-8. Therefore, the synthesised Bi@g-C3N4/ZIF-8 heterojunction photocatalysts may be used as a good photocatalyst for purifying and degrading organic matter in sewage.
Metal–organic frameworks (MOFs) have garnered significant attention in recent years due to their potential application in flame-retardant polymeric materials. In this work, Fe 2 O 3 /ZnFe 2 O 4 /g-C 3 N 4 @ZIF-8 flame retardants were synthesized via solvothermal and calcination techniques, and their elemental composition and morphologies were thoroughly characterized. The flame retardancy of polyurea (PUA) composites incorporating varying dosages of these flame retardants was evaluated using cone calorimetry tests (CCT). The findings demonstrate that the incorporation of Fe 2 O 3 /ZnFe 2 O 4 /g-C 3 N 4 @ZIF-8 significantly enhanced the flame retardant properties of PUA composites. With the addition of 3 wt% of the flame retardant, the peak heat release rate (PHRR), total heat release (THR), total smoke production (TSP), and total CO yield (TCO) of the PUA composites decreased to 890.82 kW/m 2 , 131.34 MJ/m 2 , 12.30 m 2 , and 2.39 g, respectively, reflecting reductions of 33.59%, 18.59%, 29.40%, and 47.93% compared with pure PUA. The flame-retardant mechanism was systematically analyzed in both the condensed and gas phases. This study provides a robust experimental foundation and novel insights that contribute to the development of advanced flame-retardant coating materials.
Chao Li,Juan Lu,Yanjia Guo,Jing Wang,Yujia Song,Ruidan Li,Li Tian,Xuwen Li
In this study, a solid-state electrochemiluminescence (ECL) sensor was developed for ultrasensitive and specific detection of sulfapyridine (SPY) using graphitic carbon nitride (g-C 3 N 4 ) as a luminescent reagent. The sensor was fabricated by sequentially coating composite material g-C 3 N 4 @ZIF-8 and Nafion onto the electrode surface. The g-C 3 N 4 , synthesized through high-temperature pyrolysis of melamine, generated a sensitive ECL signal in K 2 S 2 O 8 solution. And g-C 3 N 4 served as a carrier for ZIF-8, with the latter acting as a co-reaction promoter within the g-C 3 N 4 -K 2 S 2 O 8 system, leading to a significant enhancement of the ECL signal. Additionally, molecularly imprinted polymers (MIPs) with SPY were introduced to further enhance the performance of the sensor by specifically recognizing SPY. Under optimal conditions, the prepared ECL sensor showed sensitive measurement of SPY in the linear range of 5.0 × 10 −13 ∼ 5.0 × 10 −8 mol/L, with a detection limit (LOD) of 1.67 × 10 −13 (S/N = 3). The developed MIP-ECL sensor demonstrated good stability, high sensitivity, and reliable reproducibility, thus making it suitable for detecting SPY in real samples.
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