Abstract：
In the search of novel photocatalysts to increase the effect of visible light in photocatalysis, g-C3N4 (CN) has become a shining star. Rare earth metals have been used as dopant material to reinforce the photocatalytic activity of CN due to their unique electron configuration recently. In this present study, the pure and different amounts of Ho-doped g-C3N4 (HoCN) photocatalysts were successfully synthesized using urea as a precursor by the one-pot method. Morphological, structural, optical, and vibrational properties of the synthesized photocatalysts were characterized by SEM, EDX, XRD, TGA, XPS, FTIR, PL, TRPL, Raman, DRS, and BET analyses. In addition, theoretical calculations using density functional theory (DFT) were meticulously carried out to delve the changes in the structural and electronic structure of CN with holmium doping. According to calculations, the chemical potential, electrophilicity, and chemical softness are higher for HoCN, while HOMO-LUMO gap, dipole moment, and the chemical hardness are lower for the pure one. Thus, holmium doping becomes desirable with low chemical hardness which indicates more effectivity and smaller HOMO-LUMO gap designate high chemical reactivity. To determine the photocatalytic efficiency of the pure and doped CN photocatalysts, the degradation of methylene blue (MB) was monitored under visible light. The results indicate that holmium doping has improved the photocatalytic activities of CN samples. Most strikingly, this improvement is noticeable for the 0.2 mmol doped CN sample that showed two times better photocatalytic activity than the pure one.
摘要：
在寻找新型光催化剂以增加光催化中可见光的效果，g-C3N4（CN）已成为一颗闪亮的恒星。近年来，稀土金属由于其独特的电子构型而被用作掺杂剂材料以增强CN的光催化活性。在本研究中,以尿素为前体，通过一锅法成功合成了纯的和不同量的Ho掺杂的g-C3N4（HoCN）光催化剂。形态学,结构,光学，用SEM对合成的光催化剂的振动性能进行了表征,EDX,XRD,TGA,XPS,FTIR,PL,TRPL,拉曼,DRS,和BET分析。此外,使用密度泛函理论（DFT）进行了精心的理论计算，以研究掺杂的CN的结构和电子结构的变化。根据计算,化学势，亲电性,HoCN的化学柔软度更高，而HOMO-LUMO差距，偶极矩,纯的化学硬度较低。因此，在化学硬度较低的情况下，需要掺杂钬，这表明更有效，而HOMO-LUMO间隙较小则表明化学反应性较高。为了确定纯的和掺杂的CN光催化剂的光催化效率，在可见光下监测亚甲基蓝(MB)的降解。结果表明,钬掺杂提高了CN样品的光催化活性。最引人注目的是，对于0.2mmol掺杂的CN样品，这种改善是明显的，该样品显示出比纯样品好两倍的光催化活性。
