A review of metal-organic frameworks/graphitic carbon nitride composites for solar-driven green H₂ production, CO₂ reduction, and water purification

The rapid increase in population growth and economic development led to the increase in utilization of fossil fuels energy per capita. Thus, the consumption of these fossil fuel's energy resources poses serious implications for our environment. Photocatalysis plays an essential role in sustainable energy development and environmental remediation. The graphitic carbon nitride (g-C₃N₄) has been efficiently employed in photocatalysis due to its abundance, low price, high stability, appropriate band gap, and encouraging environmental impacts. As the photocatalytic efficiency of single component g-C₃N₄ is still not satisfactory for efficient photocatalysis. Hence, its composites with various functional nanomaterials have been widely prepared and employed for efficient photocatalysis. Among the widely coupled functional nanomaterials, metal-organic frameworks (MOFs) have been widely explored for energy production and controlling environmental pollution due to their large surface area, tunable pore size and window, and tailored functionalities. The significance of MOF/g-C₃N₄ composites flourished for green hydrogen (H₂) production, carbon dioxide (CO₂) conversion, and environmental pollution control. In this review, we comprehensively highlighted the recent advancements and challenges of g-C₃N₄ and MOFs heterojunctions in the field of green H₂ production. Besides, we discussed the up-to-date applications of g-C₃N₄-based composites with MOFs for CO₂ conversion to useful fuels. Furthermore, the association between MOFs and g-C₃N₄ composites and their performance for water purification are also discussed. Finally, we proposed the future potential of MOF/g-C₃N₄ composites to be used for the generation of green energy in order to solve environmental issues. We suggest that this review can help to design MOF/g-C₃N₄ composite photocatalysts for prospective applications in energy harvesting and controlling environmental pollution.