Photocatalytic dye degradation by synergistically Cu LSPR and Schottky barrier enhanced Cu/gC3N4

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.