In this paper, boron, sulfur and phosphor doped g-C₃N₄ materials (defined as CNBF, CNSF and CNPF, respectively) were successfully prepared by thermal copolymerization of dicyandiamide and imidazole ionic liquids. The CNBF catalysts exhibited significantly enhanced activity in various Knoevenagel condensation of aldehyde with malononitrile, which were typical base-catalyzed reactions, comparing with CNSF and CNPF catalysts. The detailed characterizations of Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), High angle annular dark field-scanning transmission electron microscopy (HADDF-STEM) and ¹¹B solid-state MAS NMR showed that boron was evenly doped in tri-s-triazine rings of g-C₃N₄ by substituting the carbon sites. In addition, CO₂ Temperature programed desorption (CO₂-TPD) characterizations indicated that the basic site concentration of CNBF catalysts was proportional to the doped boron content. Excluding the effect of specific surface area, the catalytic activity of CNBF catalysts followed the order CNBF-0.1 < CNBF-0.3 < CNBF-0.5 < CNBF-0.7, which was the same as that of boron content and basic site concentration. The catalytic performance revealed that boron-doping was an effective strategy to enhance the basicity of g-C₃N₄. This study will put forward the further application of boron-doped or boron-dominant two dimensional materials towards metal-free heterogeneous base catalysis.

本文通过双氰胺和咪唑离子液体的热共聚成功制备了硼，硫和磷掺杂的gC ₃ N ₄材料（分别定义为CNBF，CNSF和CNPF）。与CNSF和CNPF催化剂相比，CNBF催化剂在醛与丙二腈的各种Knoevenagel缩合反应中表现出显着增强的活性，这是典型的碱催化反应。傅里叶变换红外光谱（FT-IR），X射线衍射（XRD），X射线光电子能谱（XPS），高角度环形暗场扫描透射电子显微镜（HADDF-STEM）和¹¹ B固体的详细表征态MAS NMR表明硼均匀地掺杂在gC ₃的三-s-三嗪环中N ₄被碳原子取代。此外，CO ₂程序升温脱附（CO ₂ -TPD）表征表明，CNBF催化剂的基本位点浓度与掺杂的硼含量成正比。除比表面积的影响外，CNBF催化剂的催化活性依次为CNBF-0.1 <CNBF-0.3 <CNBF-0.5 <CNBF-0.7，与硼含量和碱性位点浓度相同。催化性能表明，硼掺杂是提高gC ₃ N ₄碱度的有效策略。。这项研究将提出掺硼或占主导地位的二维材料在无金属多相碱催化中的进一步应用。