In-depth understanding of core-shell nanoarchitecture evolution of g-C_3N_4@C, N co-doped anatase/rutile: Efficient charge separation and enhanced visible-light photocatalytic performance

摘要

Graphical abstractDisplay OmittedHighlights•Multicomponent heterojunction via facile sol-gel assisted heat treatment approach.•g-C3N4coated on anatase/rutile mixed phase at higher heat treatment temperature.•Unique band structure alignment, electron-holes separation and transport mechanism.AbstractHerein, we demonstrated the simultaneous formation of multi-component heterojunction consisting graphitic carbon nitride (g-C3N4) and C, N co-doped anatase/rutile mixed phase by using facile sol-gel assisted heat treatment. The evolution of core-shell nanostructures heterojunction formation was elucidated by varying the temperature of heat treatment from 300°C to 600°C. Homogeneous heterojunction formation between g-C3N4and anatase/rutile mixed phase was observed in gT400 with C and N doping into TiO2lattice by O substitution. The core-shell nanoarchitectures between g-C3N4as shell, and anatase/rutile mixed phase as core with C and N atoms are doped at the interstitial positions of TiO2lattice was observed in gT500. The result indicated that core-shell nanoarchitectures photocatalyst (gT500) prepared at 500 ◦C exhibited the highest photocatalytic activity in the degradation of methyl orange under visible light irradiation. Meanwhile, the possible mechanisms of charge generation, migration, action species and reaction that probably occur at the gT500 sample were also proposed. The photodegradation results of gT500 correlated completely with the results of the PEC and photoluminescence analysis, which directly evidenced improved charge separation and migration as the crucial parameters governing photocatalysis. It is worthy to note that, the simultaneous formation of multicomponent heterojunction with core-shell structure provided an enormous impact in designing highly active photocatalyst with superior interfacial charge transfer.