Bottom-to-Up synthesis of functional carbon nitride polymer: Design principles, controlled synthesis and applications

[Display omitted] •A critical review about bottom-to-up approach for synthesis of g-C3N4 polymer.•Review bottom-to-up in terms of design principles and controlled synthesis.•The Review conclude with challenges and opportunity for bottom-to-up strategy. Graphitic carbon nitride polymer (g-C3N4) plays an key role in the field of solar-to-fuel conversion and environmental remediation due to adjustable photoelectric properties, intrinsic earth-abundant nature, environmental-benign and outstanding physicochemical stability. The photoactivity is limited by rapid recombination of electron-hole pairs and sluggish kinetics. To address the issue, a diverse of hierarchical structures, shapes and dimensions have been designed and controllably synthesized at the micro/nanometer scale. Although significant achievements made, a facile, versatile and scalable bottom-up synthesis strategy seems more urgently required than the top-down route. Herein, this Review introduces the mechanisms of template methods, supramolecular preorganization assembly and template-free strategy (i.e., monomer self-template technique, monomer-free template route) for synthesizing functional g-C3N4 polymer, and then illustrates the design principles and controlled synthesis. Subsequently, summarize advancement of polymeric g-C3N4 applications in solar-to-fuels conversion and environmental remediation. Finally, this Review concludes with a summary and an invigorating perspective on the challenges, future directions at the forefront of bottom-up strategy for synthesizing functional g-C3N4 polymer. Hoped that the Review stimulates a new doorway to facilitate the generation of highly desirable, rational-design, and high-efficiency g-C3N4 polymeric catalysts for advanced applications ranging from clean fuel production to environmental decontamination.