制备类石墨相氮化碳多孔光催化剂的模板法发展

氮化碳作为一种具有高催化性能的光催化剂，具有无毒无害，自然环境下稳定的性质，在水解制氢气氧气以及降解有机污染物领域得到了广泛的关注. 其中类石墨相氮化碳(g-C₃N₄)因其特殊的片层结构而具有较高比表面积，常配合孔结构的构造，提供光生载流子及反应物质的运输通道以及大量活性位点用于氧化还原反应，是具有高光电性能的一种光催化剂.制备该种催化剂孔结构的方法有硬模板法，软模板法与非模板法，其中硬模板法需要在实验后除去模板，软模板法的模板会随着高温除去，非模板法的制备过程没有模板的参与。本文根据近年文献的整理，着重阐述和比较各制备方法的优劣，结合常用的修饰手段总结各制备方法的变化趋势和发展方向，并对后续研究中制备方法的使用前景做出判断. 

Development of template methods for the preparation of porous photocatalysts of graphite-like carbon nitride

As a metal-free photocatalyst with high catalytic performance, carbon nitride is non-toxic, harmless, and stable in the natural environment. Owing to its facile synthesis, stable physical and chemical properties, tunable structure, and suitable band gap, graphite-like carbon nitride (g-C₃N₄) plays an increasing role in the field of photocatalysis. It has attracted extensive attention in the fields of evolution of hydrogen and oxygen via water-splitting hydrolysis and in the degradation of organic pollutants. In particular, g-C₃N₄ is identified to have a high specific surface area (SSA) because of its special lamellar structure. Meanwhile, the abundant pores intrinsic in it are able to provide both transporting channels for photogenic carriers or reactive species and a large number of active sites for redox reactions. These merits endow it with high photoelectrical properties. The preparation methods of the pore structures of such catalyst include hard templates, soft templates, and non-template ones. The hard template method enables the preparation of regular pore structures but requires additional removal treatment. However, the soft templates can be decomposed during the high-temperature preparation of g-C₃N₄, which avoids the use of toxic reagents and consequently is harmless to the environment, and the template-free method does not involve any templates, which will simplify the experimental process from the aspect of sample preparation with reduced cost. In this paper, the advantages and disadvantages of various preparation methods were elaborated and compared based on the literature review in recent years. The developments and applications in the environmental and energy aspects were summarized by combining the commonly used modification methods, which provided the perceptions with respect to the development of metal-free g-C₃N₄-based photocatalysts in the future. Further, the photocatalytic mechanism was explained, and the four different precursors of g-C₃N₄ were compared. Finally, the ongoing outlook and perspectives will be covered in this review.