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

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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.