Boosting Rh@S1–TiNbS 4 Single‐Atom Electrocatalyst for Oxygen Evolution Reaction via Strain Modulation

ABSTRACT Designing high‐efficiency oxygen evolution reaction (OER) electrocatalysts is hindered by high overpotentials and the reliance on precious metals. To address this, we designed a series of single‐atom catalysts by anchoring transition metal atoms (TM = Co, Ni, Rh, Pd, Ir, Pt) into stable S1 vacancy of TiNbS 4 (TM@S1–TiNbS 4 ) and systematically evaluated their catalytic performance using density functional theory (DFT) calculations. Notably, Ni‐, Rh‐, and Pt‐doped systems exhibited outstanding OER activity, with low overpotentials in the range of 0.45 ∼ 0.51 V, outperforming the benchmark IrO 2 catalyst of 0.56 V. We further identified the O* adsorption free energy and the d‐electron number of the TM atoms as effective descriptors for OER. In addition, molecular orbital analysis revealed that the hybridization between TM‐d orbital and O‐ p orbitals (π* antibonding) facilitates appropriate adsorption of oxygen intermediate on the active sites, thereby enhancing OER activity. Furthermore, biaxial strain was utilized to optimize OER performance of representative Rh@S1–TiNbS 4 , shifting its activity closer to the peak of the volcano plot. Apparently, Rh@S1–TiNbS 4 showed the lowest overpotential of 0.40 V under a 2% biaxial tensile strain. This work not only proposes a promising class of single‐atom catalyst for OER but also provides fundamental insights into a practical strain‐engineering strategy for advancing electrocatalytic performance.