Molten salt-assisted shape modification of CaFe2O4 nanorods for highly efficient photocatalytic degradation of methylene blue

Abstract CaFe2O4 nanorods (CFO NRs) and aggregated particles (CFO APs) were fabricated with and without the help of molten salt-assisted shape modification, respectively. CFO APs present inferior photocatalytic performance due to the plenty of grain boundaries which hinder photogenerated charges transfer and act as charge recombination sites. Molten salt-assisted modification can easily changes the shape of CFO NRs and significantly suppresses the formation of grain boundaries, facilitating photogenerated charges separation and transfer for highly efficient photocatalytic degradation of methylene blue (MB). Surface state investigation indicates a decreased amount of unsuitable oxygen vacancies and defects in CFO NRs, which is beneficial in alleviating the recombination of photogenerated charges in CFO NRs. The CFO NRs show a ten-time increased kinetic constant of MB degradation from 0.0013 to 0.013 min−1 by virtue of the alleviative charge recombination.