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The issue of water pollution has emerged as a formidable challenge, prompting a pressing need for solutions. The utilization of metal nanoparticles with surface plasmon resonance and semiconductor composite photocatalysts is regarded as a highly effective approach to solve this problem. g-C3N4 is an effective catalyst for the degradation of organic pollutants. Its photocatalytic performance is usually enhanced by the use of the noble metal Au Ag. However, the high cost of these materials limits their application. In this study, we present the synthesis of Al NPs/g-C3N4 nanocomposites using the bridging effect of ligands. The characterized of transmission electron microscopy (TEM), X-ray diffractometer (XRD) and ultraviolet-visible spectroscopy (UV-Vis) proved that Al NPs/g-C3N4 with a wider light absorption range were successfully synthesized. The effects of ligands, (glutathione (GSH), glutamic acid (GAG), and cysteine (CYS)), Al diameter (40 to 200 nm) and the ratio of Al to g-C3N4 (1:1 to 5:1) on the photocatalytic degradation of methylene blue (MB) by Al NPs/g-C3N4 were also evaluated. The results showed that the optimum degradation efficiency of Al NPs/g-C3N4 for MB at 5 mg/L reached 100% within 60 min, which was 11 times higher than that of pure g-C3N4. The principal analysis of Al enhancing the photocatalytic performance of g-C3N4 was studied through transient photocurrent spectroscopy (TPC), electrochemical impedance spectroscopy (EIS), and steady-state transient fluorescence spectroscopy (PL). The results confirmed that hot carriers generated by localized surface plasmon resonance (LSPR) of Al nanoparticles increase the carrier concentration. In addition, the Schottky barrier generated by Al and g-C3N4 could also improve the carrier separation rate and increase the carrier lifetime. This work is expected to solve the problem of organic wastewater treatment and lay the foundation for subsequent research on photocatalysis. [ABSTRACT FROM AUTHOR]

[Display omitted] Localized surface plasmon resonances of the Al-NPs enhance the photocatalysis performances of Al-NPs/ TiO 2. • Al-NPs/TiO 2 are prepared by using GSH ligand compound as linking bridge. • FDTD simulation reveal the LSPR of 70 nm Al-NPs have a strong coupling with the TiO 2 band gap. • XPS and FTIR measurements confirm that a stable bond formed between Al-NPs and TiO 2. • The LSPR effect of Al-NPs can significantly enhance the photocatalytic efficiency of TiO 2. Al nanoparticles composited with TiO 2 (Al-NPs/TiO 2) has drawn considerable attention over the years due to the localized surface plasmon resonance (LSPR) effect of Al-NPs can significantly enhance the photocatalytic efficiency of TiO 2. However, most of the Al-NPs were obtained on Al substrates which limited its practical application. Herein, the isolated Al-NPs were composited together with the TiO 2 by using glutathione (GSH) as linking bridge in aqueous environment. Finite difference time domain (FDTD) simulation was used to reveal the LSPR absorption of Al-NPs. The results show that the LSPR of 70 nm Al-NPs have a strong coupling with the TiO 2 band gap. The X-ray diffraction analysis and TEM images show that our sample are pure, and the TiO 2 indeed composite on the surface of Al-NPs under the action of GSH ligand bridge as seen in the TEM images. This ligand bridge was further verified by the FTIR and XPS measurements. The EPR experiment indicate the OH signals of Al-NPs/TiO 2 are higher than that of pure TiO 2 because of enhanced charge separation and transfer. The photodegradation experiment show that Al-NPs/TiO 2 can rapidly degrade the concentration of methylene blue (MB) to zero under UV–vis light illumination in 70 min. All the above results indicate that the Al-NPs can significantly enhance the photocatalytic efficiency of TiO 2 which due to the LSPR effect of Al. [ABSTRACT FROM AUTHOR]

The issue of water pollution has emerged as a formidable challenge, prompting a pressing need for solutions. The utilization of metal nanoparticles with surface plasmon resonance and semiconductor composite photocatalysts is regarded as a highly effective approach to solve this problem. g C 3 N 4 is an effective catalyst for the degradation of organic pollutants. Its photocatalytic performance could be enhanced by the use of the metal such as Au, Ag, and Cu. However, the Schottky barrier is generally believed to be the reason that Cu can enhances the photocatalytic performance of g C 3 N 4. In fact, the plasmonic of Cu will also have an effect on the photocatalytic effect of g C 3 N 4 , like Au and Ag. In this study, it is first proposed that the photocatalytic performance of g C 3 N 4 can be enhanced by combining the plasmonic of Cu and the Schottky barrier. Cu g/C 3 N 4 nanocomposites with stable crystal structure, with Cu as the core and g C 3 N 4 as surface coating, were synthesized and characterized by transmission electron microscopy (TEM), X ray diffractometer (XRD) and ultraviolet visible spectroscopy (UV Vis) and X ray photoelectron spectroscopy (XPS). Then, it is optimized that the Cu/g C 3 N 4 composite material which were prepared with 200 nm Cu particles, GSH as the ligand bridge, and a Cu: g C 3 N 4 ratio of 5:1, have the best photocatalytic property, which is 16.7 times of the photocatalytic property of g C 3 N 4. Besides, the transfer efficiency of hot electrons of 33% (from Cu to g C 3 N 4) under the influence of the Schottky barrier (0.58 eV) is calculated theoretically. On this basis, the mechanism of Cu nanoparticles enhancing the photocatalytic performance of g C 3 N 4 was also been proved through the calculation result and transient photocurrent spectroscopy (TPC), electrochemical impedance spectroscopy (EIS), and steady state transient fluorescence spectroscopy (PL) characterization. The excellent photocatalytic performance of the Cu/g C 3 N 4 composites is due to the simultaneous influence of Schottky barrier and LSPR of Cu. [Display omitted] • The photocatalytic performance of g-C 3 N 4 can be enhanced by combining the LSPR properties of Cu and the Schottky barrier. • The effect of Cu LSPR on the photocatalysis of g-C 3 N 4 was first discussed by using the thermal electron transfer efficiency. • The physical mechanism of Cu-enhanced the photocatalysis of g-C 3 N 4 is discussed. [ABSTRACT FROM AUTHOR]