Lattice Strained Induced Spin Regulation in Co-N/S Coordination-Framework Enhanced Oxygen Reduction Reaction.

Oxygen reduction reaction (ORR) is the bottleneck of metal-air batteries and fuel cells. Strain regulation can change the geometry and adjust the surface charge distribution of catalysts, which is a powerful strategy to optimize the ORR activity. The introduction of controlled strain to the material is still difficult to achieve. Herein, we present a temperature-pressure-induced strategy to achieve the controlled lattice strain for metal coordination polymers. Through the systematic study of the strain effect on ORR performance, the relationship between geometric and electronic effects is further understood and confirmed. The strained Co-DABDT (DABDT=2,5-diaminobenzene-1,4-dithiol) with 2 % lattice compression exhibits a superior half-wave potential of 0.81 V. Theoretical analysis reveals that the lattice strain changes spin-charge densities around S atoms for Co-DABDT, and then regulates the hydrogen bond interaction with intermediates to promote the ORR catalytic process. This work helps to understand the catalytic mechanism from the atomic level.