In situ construction of yolk-shell zinc ferrite with carbon and nitrogen co-doping for highly efficient solar light harvesting and improved catalytic performance.

In this work, carbon and nitrogen co-doped yolk-shell ZnFe2O4 nanostructures (CN-ZnFe2O4) were successfully synthesized through a facile self-templated method with in situ doping strategy. A series of characterizations were processed to present a comprehensive properties of the as-prepared photocatalyst samples. Doping amount could be moderated by the addition mass of dopamine, which was regarded as both the carbon and nitrogen source. And the void space between yolk and shell could be adjusted by heating rates in the calcination process of precursors. With an excellent separation efficiency of photogenerated electron-hole pairs and transfer efficiency of photogenerated electrons, the obtained CN-ZnFe2O4 sample exhibited an enhanced visible light response than ZnFe2O4. And their photocatalytic performances towards gaseous 1, 2-dichlorobenzene (o-DCB) was also systematically studied. The results demonstrated that the CN-ZnFe2O4 sample with 100 mg dopamine addition and 20 °C/min calcination heating rate exhibited the best o-DCB degradation efficiency. In situ Fourier Transform infrared (FTIR) spectroscopy was also recorded to give a detailed information of intermediate products and reveal the mechanism of photocatalytic degradation towards o-DCB. Particularly, density functional theory (DFT) calculation was used to further study the electronic structure of prepared samples to support the experimental results and especially explain the mechanism of enhanced photocatalytic activity through a proposed lattice junction. Additionally, electron paramagnetic resonance (EPR) technique was carried out to prove the reactive oxygen species involved in the photodegradation process. This work not only presents a promising strategy in photocatalyst fabrication but also provides a new sight of enhanced photocatalysis mechanism.