Strain adjustment Pt-doped Ti₂CO₂ as an efficient bifunctional catalyst for oxygen reduction reactions and oxygen evolution reactions by first-principles calculations

The design and development of oxygen reduction reactions (ORR) and oxygen evolution reactions (OER) bifunctional single-atom catalysts with high stability, low cost and high activity are still a huge challenge. Here, based on the idea that strains can regulate the electronic structure of the catalyst, an efficient bifunctional ORR/OER catalyst Pt-doped Ti₂CO₂ (Pt-V_O-Ti₂CO₂) under 6% strain was reported using the first-principles calculations. Specifically, the phonon dispersion, structure, and energy calculation results proved that the Pt-V_O-Ti₂CO₂ keeps excellent stability under the strain range. Moreover, the d-band center of Pt atom in Pt-V_O-Ti₂CO₂ moving to the Fermi level with the increasing of the strains. In particular, the Pt-V_O-Ti₂CO₂ with solvation effects has the low overpotential of 0.41 V, 0.31 V and 0.72 V for ORR, OER and bifunctional ORR/OER under 6% strain, respectively, indicating better catalytic performance than landmark catalysts Pt (1 0 0) and RuO₂. More importantly, the theoretical polarization curve of our calculation results can be more intuitively compared with the experimental results. Additionally, the Pt-V_O-Ti₂CO₂ has a significant inhibitory effect on hydrogen evolution reaction (HER), ensuring the absolute priority of ORR and OER. Our research uncovers a highly active catalyst and guides the design and development of high-performance bifunctional catalysts.