Acid treatment enhances the methane combustion activity of LaFeO3 perovskite catalyst.

The catalytic combustion of methane has gained much attention as a sustainable technology, due to concerns about the environmental impact of unburnt methane emissions from the natural gas vehicles. Researchers have explored alternatives to precious metal catalysts for methane combustion, with a focus on perovskite oxides known for their excellent activity and sintering-resistance capacity. In this study, LaFeO 3 perovskite material was synthesized and subsequently subjected to a nitric acid etching treatment to modify its surface. It was found that the acid preferentially dissolved La cations from LaFeO 3 surface while the perovskite phase was unchanged, as a consequence, the etched LaFeO 3 shows improvement in methane combustion activity. The best performance was achieved in the sample with one-hour surface etched treatment, which suggests that the appropriate surface reconstruction induced by acid treatment promotes the formation of more active Fe sites on the surface and reduces the energic barriers of methane activation. This work presents a straightforward and effective approach to tailor the exposed surface properties of perovskites, thereby enhancing their activity in hydrocarbon combustion reactions. [Display omitted] • Nitrate acid treatment is performed to selectively etch the as-prepared LaFeO 3 perovskite for the surface modification. • Nitric acid preferentially dissolves La cations from LaFeO 3 surface, thus more Fe-O termination are exposed as active sites. • 1-h treated LaFeO 3 shows an enhanced CH 4 combustion reaction activity, due to the lowest energic barriers of CH 4 activation. • This work presents an effective approach to tailor the exposed surface properties of perovskites. [ABSTRACT FROM AUTHOR]