The surface properties of La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF) perovskite electrode are modified with HNO₃ treatment to improve its catalytic activity towards oxygen reduction reaction between 500–650 °C. The surface concentrations of A-site cations are reduced after the acid etching. After the calcination at 1150 °C, severe segregation of Sr is observed on the surface of untreated LSCF powder, which is suppressed remarkably with the HNO₃ pretreatment. Highly reactive oxygen species and Fe⁴⁺ species are formed on the surface of LSCF after the HNO₃ treatment, which are beneficial to oxygen reduction reaction. The reduction of oxygen species adsorbed on the LSCF surface, the rate-determining step of the electrode process, is accelerated significantly with the acid etching.

用HNO ₃处理可改善La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O3 _-δ（LSCF）钙钛矿电极的表面性能，以提高其对500–650°C之间的氧还原反应的催化活性。酸蚀后，A位阳离子的表面浓度降低。在1150°C下煅烧后，在未处理的LSCF粉末表面观察到Sr的严重偏析，而HNO ₃预处理可明显抑制Sr偏析。HNO ₃后在LSCF的表面形成高活性氧和Fe ^4+。处理，有利于氧还原反应。电极蚀刻的速率决定步骤，通过酸蚀刻大大加快了LSCF表面上吸附的氧种类的减少。