Synthesis of SnO₂/yolk-shell LaFeO₃ nanocomposites as efficient visible-light photocatalysts for 2,4-dichlorophenol degradation

Herein, yolk-shell LaFeO₃ (YS-LFO) microsphere has been successfully prepared by a carbon microsphere (CMS) template-adsorption-calcination method. It was confirmed that the YS-LFO microspheres showed high visible-light photoactivities for 2,4-dichlorophenol degradation as compared to bare LaFeO₃ (LFO) nanoparticles, attributing to the unique yolk-shell structure and the increased surface area. The visible-light photocatalytic activities of YS-LFO microspheres could be further promoted by coupling with SnO₂ (SO) nanoparticles. Based on the surface photovoltage spectra, photoelectrochemical measurements and other characterization, it was demonstrated that the coupled SO afforded a thermodynamically suitable platform for accepting the high-level energy electrons from LaFeO₃ so as to enhance the charge separation. Compared with YS-LFO microspheres and LFO nanoparticles, the amount optimized (10SO/YS-LFO) nanocomposites displayed 1.6 and 4.7-time enhancement for 2,4-dichlorophenol degradation under visible-light irradiation, respectively. This efficient strategy of morphology controlling and photoelectron modulating could pave the approach to design high-activity visible-light driven photocatalysts.