Interfacial coupling enhanced photocatalytic activity: an experimental/DFT combined study of porous graphitic carbon nitride/carbon composite material

To produce sustainable energy and enhance the utilization efficiency of renewable natural resources, cellulose has been exploited as template to fabricate the g-C3N4/C composite via a facile hydrothermal approach. Herein cellulose acts as sacrificial template, providing rich carbon source and shaping up porous microstructure. The g-C3N4/C composite features the morphology of porous sheets, where graphitic carbon nitride and carbon components co-exist. It is evident that some cellulose-derived carbon spheres possess abundant oxygen-containing functional groups, enabling them to adsorb phenol pollutant and subsequently enhance the removal activity. Also having the ability to gather pollutants, the g-C3N4 component photocatalytically degrades phenol in a highly-efficient manner. The representative sample g-C3N4/C-140 reaches 83% removal efficiency, which is threefold higher than pristine g-C3N4. Furthermore, g-C3N4/cellulose and g-C3N4/C composites were investigated using density functional theory. The photocatalytic process and mechanism of adsorbing and degrading phenol pollutant has been revealed in conjunction with experimental findings.Graphical abstract Aiming to make full use of cellulose and mitigate carbon emission, porously structured composite g-C3N4/C was successfully fabricated. The synergetic effect of both components enhanced photocatalytic performance, whose efficiency toward phenol is threefold as high as g-C3N4. The chemical interfacial coupling calculated by DFT is strong enough to facilitate charge carriers to pass through interfaces of heterojunction and thus improve electron–hole separation efficiency. The catalytic mechanism was rationalized by computation and experiment.