From Single Atom to Five-Atom Cluster Catalysts on Boron-Doped Diamond: Interface Engineering and Dynamic Active Sites Exploration for Acidic OER

The exceptional electrochemical stability of boron-doped diamond (BDD) makes it a promising oxygen evolution reaction (OER) anode in acidic media for proton exchange membrane water electrolyzers; however, its inertness leads to high overpotentials (η). To overcome this activity-stability conflict, we employ atomic-scale interface engineering via single-atom catalysts (SACs) and single-cluster catalysts (SCCs) anchored on BDD. Employing structure prediction and density functional theory (DFT) framework, we screen 28 SACs and 16 SCCs (including α and β isomers). Through stability assessments (formation energies, dissolution potentials, and diffusion barriers), M@BDD and M 5 @BDD-α/β (M = Fe, Co, Ni, Cu, and Pt) are identified as promising catalysts following the adsorbate evolution mechanism. Conventional descriptor analysis (η OER vs Δ G *O -Δ G *OH ) reveals a volcano-type activity trend, and η OER exhibits a strong linear correlation with Δ G *OOH . Crucially, a dynamic reaction pathway is unveiled where proton-coupled electron transfer and *O adsorption on Ni 5 @BDD-α/β trigger a dramatic reduction in the isomerization barrier, driving a thermodynamically favorable symmetry breaking and establishing a new multicenter bonding-mode. This active site evolution thereby circumvents the rate-determining step identified in static models, achieving a lower η of 0.56 V. This work establishes a design principle for BDD-based catalysts and provides fundamental insight into dynamic active sites.