Selective corrosion of LaCoO 3 by NaOH: structural evolution and enhanced activity for benzene oxidation

La(OH) 3 nanosheets have been successfully coated on electrospun LaCoO 3 nanorods using a simple and facile corrosion process, where La cations are selectively precipitated using NaOH. During the oxidation process, La(OH) 3 is converted to La 2 O 3 having a mutual effect with the spontaneously generated Co 3 O 4 and the predominant LaCoO 3 component. The performances for catalytic benzene oxidation and characterization results indicate that the alkaline treatment of electrospun LaCoO 3 can improve the apparent catalytic activity because more surface adsorbed oxygen species and exposed Co 3+ are generated. However, if the treatment time reaches 9 h, over-deposition of La(OH) 3 /La 2 O 3 species on the surface may cause a large fraction of active Co species to be inaccessible, resulting in a lower specific activity (2.9 × 10 −6 mol C6H6 m −2 h −1 ) compared to that of untreated LaCoO 3 (4.8 × 10 −6 mol C6H6 m −2 h −1 ). A treatment time of 3 h provides the highest specific activity, 1.01 × 10 −5 mol C6H6 m −2 h −1 . Moreover, the obtained catalyst shows deactivation of only 3% benzene conversion in a stability test at 450 °C for 48 h. Therefore, NaOH-treated LaCoO 3 is a promising catalyst for the practical removal of volatile organic compounds due to its high efficiency, good stability, and convenient preparation.