Efficient Reduction of Low-Concentration NO via Dendritically Channeled Solid Oxide Cells

Gaseous NOx emission is a critical environmental challenge. Since conventional methods for catalytic reduction of NOx from exhaust gases suffer from secondary pollution and low conversion efficiencies, electrochemical reduction via solid oxide cells (SOCs) offers great promises to effectively address these issues. Herein, for the first time, we demonstrated that low-concentration NO could be efficiently reduced over the same SOCs under both solid oxide fuel cell and solid oxide electrolysis cell conditions, which provides promising flexibility in cell operation conditions so that it would not be restrained by the availability of intermittent renewable power. To address the low-concentration issue (less than 2%) of NO, we proposed dendritically channeled supporting perovskite cathodes with an ultra-fast NO diffusion pathway to reaction sites at the cathode/electrolyte interface and more reaction sites for conducting NO reduction, resulting in an increase of 66.9–74.2% in electrolysis current density as well as stable operation. Moreover, such a channel structure not only effectively facilitated the coating of nanocatalysts via a simple impregnation process but also enabled the co-sintering of cathode supports and electrolytes at high temperatures during cell preparation owing to high sintering resistance. This work provides a protocol for rationally designable fabrication of high-performance dendritically channeled SOCs for applications in hazardous gas conversion.