Scalable preparation of g-C3N4 nanosheets and quantum dots for metal anode protection and nitrogen reduction

石墨化碳氮化物(g-C3N4)是一种新兴的二维半导体材料，由碳和氮通过三氮杂环连接而成。它类似于N掺杂石墨烯，但具有更高的N含量和清晰的三角亚纳米孔(~0.7 nm)。其独特的、可调的光学、化学和催化性能，加上其低廉的价格和对氧化的高度稳定性(高达500℃)，使其成为许多应用的诱人材料，包括在光电催化、充电电池、太阳能电池、超滤和超硬涂层中。与已经商业化生产的石墨烯相比，二维g-C3N4纳米材料仍处于开发的早期阶段，提供了巨大的商业化机会。通常情况下，g-C3N4是通过三聚氰胺单体在高温下聚合和焙烧合成的。我们最近在合成中引入了超分子组装的概念。也就是说，其他含氮单体首先与三聚氰胺一起组装成超分子，然后通过精确的结构控制焙烧得到g-C3N4。由此得到的g-C3N4量子点和g-C3N4纳米片可以显著提高锂和锌金属阳极的稳定性，为电动汽车用锂离子和锌离子电池的长循环寿命和固定储能铺平了道路。在我们的初步测试中，g-C3N4可以作为光催化剂将氮还原为氨，有可能导致绿色肥料。在这里，我们建议设计一种可扩展的工艺来制备具有精确控制的电子结构和多孔结构的g-C3N4纳米材料，用于电池和氮气还原应用。将进行理论建模以指导设计。我们期待着一种随时可以商业化的g-C3N4添加剂来改善电池的循环寿命，以及一种有前途的g-C3N4光电催化剂，以在项目结束时为艾伯塔省的农业合成绿色肥料。未来，同样的概念将被应用于许多其他应用，例如，选择性地分离艾伯塔省石油和天然气卤水中的锂。

Graphitic carbon nitride (g-C3N4) is an emerging 2D semiconductor consisting of C and N, connected via tris-triazine-based patterns. It is analogous to N-doped graphene but with much higher N content and well-defined trigonal sub-nano pores (~ 0.7 nm). Its unique and tunable optical, chemical, and catalytic properties, alongside its low price and high stability to oxidation (up to 500C), make it a attractive material for numerous applications, including in photo- and electro-catalysis, rechargeable batteries, solar cells, ultrafiltration, and super hard coating. Compared to graphene already in commercial production, 2D g-C3N4 nanomaterials are still in the early stage of development and provide tremendous commercialization opportunities. Typically, g-C3N4 is synthesized through the polymerization and calcination of melamine monomer at high temperatures. We recently introduced a supramolecular assembly concept in the synthesis. Namely, other nitrogen-containing monomers were first assembled into supramolecular together with melamine and then calcined into g-C3N4 with precise structure control. The resulting g-C3N4 quantum dots and g-C3N4 nanosheets can significantly improve the stability of Li and Zn metal anodes, which paves the road for long cycle life Li-ion and Zn-ion batteries for electric vehicles and stationary energy storage. In our preliminary test, g-C3N4 can serve as a photocatalyst to reduce nitrogen into ammonia, potentially leading to green fertilizer. Herein, we propose to design a scalable procedure to fabricate g-C3N4 nanomaterials with precisely controlled electronic and porous structures for battery and nitrogen-reduction applications. Theoretical modeling will be conducted to guide the design. We are expecting a ready-to-commercialize g-C3N4-based additive to improve the cycle-life batteries and a promising g-C3N4 photoelectrocatalyst to synthesis green fertilizer for Alberta agriculture at the end of the project. In the future, the same concept will be adapted to many other applications, e.g., selectively separating lithium in Alberta oil and gas brine.