Highly stable and efficient Pt single-atom catalyst for reversible proton-conducting solid oxide cells

Reversible proton-conducting solid oxide cells (R-PSOCs) have been proposed to address energy storage and conversion challenges. However, under harsh operating conditions (550 °C ~700 °C containing CO 2 and H 2 O), the application of single-atom catalysts (SACs) in R-PSOCs is challenging due to the migration/agglomeration of isolated atoms and the lack of universal processing techniques for catalyst loading. Here, we firstly report a single-atom customizing strategy to create four-coordinated Pt-O-Ni (4) that selective anchors Pt atoms to the B-site in Pr 4 Ni 3 O 10+δ . The resultant SAC is thermally stable, controllable, and highly active for oxygen reduction and oxygen evolution reactions, withstanding treatment at 700 °C for 800 h in air, and its electrochemical performance was improved by almost 100%. This work bridges the application gap between SACs and R-PSOCs, are amenable to the large-scale manufacture of stable, efficient, high-loading SACs for industrial applications, which can also be extended to Pd, Ir, Ru, and Fe SACs. Strong metal support interaction is crucial for designing anchor structures to thermally stable single-atom, but limited by preparation methods and the contradiction between activity and stability. A universal customization strategy using Pr 4 Ni 3 O 10+δ as support is proposed to resolve these challenges, for obtaining the SACs with superior stability, excellent efficiency, and scalable production (100 g in our work), under high temperature for reversible proton-conducting solid oxide cells. In addition, the proposed preparation route can be extended to monoatomic Pt, Ru, Pd, Ir, and Fe on the PNO surface. • A new highly stable and efficient Pt SAC for R-PSOC was obtained by a simple, versatile and scalable method. • Two new reaction sites with strong CMSI were discovered and can be regulated to boost the activity of ORR and OER. • The local electronic and spatial structures of the two reaction sites were revealed by EXAFS, AC-HAADF-STEM, NAP-XPS and DFT calculations. • This SAC customized route can be generally extended to prepare other systems such as Pd, Ir, Ru, and Fe SACs.