Poly(heptazine imide) (PHI), one of the crystalline or long-range ordered allotropes of polymeric carbon nitride, is a promising polymeric photocatalyst; however, preparation of highly crystalline PHI remains a challenge. Herein, through a bottom-up strategy involving repair of structural defects and increase of specific surface area of melon precursor, we prepared PHI nanorods with dramatically improved long-range order. The resulting PHI exhibited a shift of product selectivity in CO2 photoreduction from CO to CH4 with a high methanation activity in contrast to the pristine PHI with relatively low long-range order. The improvement of long-range order for PHI remarkably enhanced the separation efficiency and transfer dynamics of photogenerated charges as well as the adsorption capacity for *CO intermediate. This study revealed the relationship between the precursor structure and PHI crystal growth in ionothermal synthesis, and also showcased the great potential of highly crystalline PHI in artificial photosynthesis.

中文翻译：

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自下而上的策略增强聚庚嗪酰亚胺纳米棒的长程有序性，用于高效的光催化 CO2 甲烷化


聚庚嗪酰亚胺 （PHI） 是聚合物氮化碳的结晶或长程有序同素异形体之一，是一种很有前途的聚合物光催化剂;然而，制备高度结晶的 PHI 仍然是一个挑战。在此，通过涉及修复结构缺陷和增加甜瓜前驱体比表面积的自下而上的策略，我们制备了具有显着改善长程有序的 PHI 纳米棒。所得 PHI 在 CO2 光还原中表现出产物选择性从 CO 转变为具有高甲烷化活性的 CH4，而原始 PHI 具有相对较低的长程顺序。PHI 长程有序的提高显著提高了光生电荷的分离效率和传递动力学，以及 *CO 中间体的吸附能力。这项研究揭示了电离热合成中前驱体结构与 PHI 晶体生长之间的关系，也展示了高结晶 PHI 在人工光合作用中的巨大潜力。