Atom trapping of scarce precious metals onto a suitable support at high temperatures has emerged as an effective approach to build thermally stable single-atom catalysts. Here, following a similar mechanism based on atom trapping through support effects, we demonstrate a reverse atom-trapping strategy to controllably extract strontium atoms from a rigid lanthanum strontium cobalt ferrite ((La_0.6Sr_0.4)_0.95Co_0.2Fe_0.8O_3−δ, LSCF) surface with ease. The lattice oxygen redox activity of LSCF is accordingly fine-tuned, leading to enhanced cathode performance in a solid-oxide fuel cell. An over 30−70% increases in maximum power density of the single cells at intermediate temperatures is achieved by LSCF with surface strontium vacancies compared to the pristine surface. In addition, the strontium-deficient surface excludes strontium segregation and formation of electrochemically inert SrO islands, thus improving the longevity of the cathode. This development can be broadly applicable for modifying structurally stable oxide surfaces, and opens more possibilities of scalable single-atom extraction strategies.

在高温下将稀有贵金属原子捕获到合适的载体上已成为构建热稳定单原子催化剂的有效方法。在这里，遵循基于通过支持效应捕获原子的类似机制，我们展示了一种反向原子捕获策略，可从刚性镧锶钴铁氧体 ((La _0.6 Sr _0.4 ) _0.95 Co _0.2 Fe _0.8 O _{3− δ}, LSCF) 表面轻松。LSCF 的晶格氧氧化还原活性因此得到微调，从而提高了固体氧化物燃料电池的阴极性能。与原始表面相比，具有表面锶空位的 LSCF 使单电池在中间温度下的最大功率密度增加了 30-70% 以上。此外，缺乏锶的表面排除了锶偏析和电化学惰性 SrO 岛的形成，从而提高了阴极的寿命。这一发展可广泛应用于修饰结构稳定的氧化物表面，并为可扩展的单原子提取策略开辟了更多可能性。