Carbon nitride based nanoarchitectonics for nature-inspired photocatalytic CO2 reduction

Drawing inspiration from the natural process of photosynthesis found in plant leaves, scientists are exploring the use of photocatalysis to convert carbon dioxide (CO2) into valuable products using solar light and water. Photocatalytic CO2 conversion has emerged as one of the efficient green approaches to revitalize the environment from greenhouse gas pollution. Owing to its visible-range band gap, non-toxicity, ease of synthesis at economic costs and stability under light irradiation, g-C3N4 has emerged as the most explored photocatalyst. However, due to rampant exciton recombination owing to poor electrical conductivity, the efficiency of CO2 reduction falls short for g-C3N4 in its pure/pristine form. Therefore, the structural manoeuvre of g-C3N4 materials using N-rich configurations, heteroatom/single-atom doping and hybridization with various functional materials including metal oxides/sulfides, perovskite halides and metal complexes has been adopted, thereby overcoming their inherent drawbacks in photocatalytic CO2 reduction. In this timely review, we present an overview of the recent advances in surface/interface engineering of carbon nitrides for the conversion of CO2 to fuels and useful chemical by-products. More importance is given to the critical evaluation of surface manipulation in carbon nitrides and how it amplifies and affects their photocatalytic properties in CO2 reduction. Finally, we provide a comprehensive outlook into the future directions of these functionalised carbon nitrides for various applications. We strongly believe that this unique review will offer new knowledge on the surface property relationship of carbon nitride-based materials and their impact on enhancing their performance in various photocatalytic reactions and further create new opportunities for them in various areas.