Solving the Trifunctional Activity Challenge of Catalysts in Unitized Regenerative Fuel Cells via 1T-MoS₂-Coordinated...

Developing high-efficiency and low-cost multifunctional electrocatalysts is the core of unitized regenerative fuel cells (URFC), yet it remains a great challenge. Here, by performing first-principles calculations, we report the atomic-level electrocatalytic activity mechanism of 3d, 4d, and 5d monoatomic transition metals (TM) bound to the 1T-MoS₂ monolayer for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). Their structural stabilities are evaluated via the formation energy, elastic constant, and molecular dynamics simulations. Compared with the Co-N₄-C single atom catalyst (SAC), the resulting Pd@1T-MoS₂ SAC exhibits better bifunctional catalytic activity, with OER overpotential as low as 0.43 V and an ORR overpotential of 0.40 V. The dual volcano plot demonstrates that the bifunctional OER and ORR activities of Pd@1T-MoS₂ originate from the neither strong nor weak OH* adsorption and the suitable d-band center (-1.83 eV) of the Pd active center. In conjunction with the intrinsic activity of the 1T-MoS₂ monolayer for hydrogen evolution reaction, the Pd@1T-MoS₂ SAC is a competitive and promising trifunctional electrocatalyst for sustainable energy conversion and storage systems.