Comparative investigation of visible-light-induced benzene degradation on M-ferrite/hematite (M = Ca, Mg, Zn) nanospheres by in situ FTIR: Intermediates and reaction mechanism

M-ferrite/hematite (M = Ca, Mg, Zn) nanospheres were fabricated by a facile solvothermal synthesis and subsequent calcination, and their performance on benzene photocatalytic degradation was effectively investigated by using in situ FTIR. The nanosphere samples were characterized with FESEM, TEM, XRD, FTIR, and UV-vis-DRS techniques. M-ferrite/hematite nanospheres were well dispersed with diameters ranging from 200 to 300 nm, and Ca-Fe-oxide nanospheres were solid, while Mg-Fe-oxide and Zn-Fe-oxide samples were hollow nanospheres. The energy gaps of the nanospheres were found approximately to be 1.95, 1.97, and 2.00 eV for Ca-Fe-oxide, Mg-Fe-oxide, and Zn-Fe-oxide, respectively. The order of the photocatalytic performance of M-ferrite/hematite nanospheres was considered as Zn-Fe-oxide > Mg-Fe-oxide > Ca-Fe-oxide through analysis of their differences on morphology, photo-absorbance property and photocatalytic conversion of benzene. By in situ FTIR, ester, carboxylic acid, aldehyde, and quinone were investigated as intermediates, and CO2 as the final product, and thereby the possible degradation pathways and mechanism of benzene were speculated further.

Automated summary

The study demonstrated that M-ferrite/hematite (M = Ca, Mg, Zn) nanospheres synthesized by solvothermal synthesis and calcination showed good performance in benzene photocatalytic degradation, with Zn-Fe-oxide exhibiting the best photocatalytic activity. Through in situ FTIR analysis, intermediates and final products of benzene degradation were identified, providing insights into possible degradation pathways and mechanisms.