Layered Porous Nanocubes: Harnessing Trimetallic PBA@WS ₂ –Phosphorus Hybrid Architecture for Efficient Oxygen Evolution

The rational assembly of multiple components in electrocatalyst design offers a promising strategy to enhance sluggish oxygen evolution reaction (OER) kinetics. However, the maximum utilization of such complex systems requires an understanding of each component's role and precise nanoscale control to uncover meaningful structure-activity relationships. This work presents a stepwise approach to designing a high-performance OER precatalyst by combining trimetallic Prussian blue analogs (PBAs), WS₂ nanosheets, and phosphorus doping, thereby forming a cooperative network within the designed M-S-P heterojunction. Each step addresses a specific challenge, ranging from structural templating and active-site enrichment to electronic modulation and mass-transport optimization. The heterojunction establishes a unique interfacial architecture in which both S and P anions are electronically bridged to transition-metal centers. Multiple metals in a core-shell configuration introduce redox diversity, enabling cooperative electron transfer and distributing the oxidative burden across neighboring sites. The dual anions play distinct yet complementary roles: the P anion accelerates proton transfer, while the S anion improves adsorption kinetics by donating electrons to stabilize OH* and OOH* intermediates. Under operating conditions, the precatalyst undergoes in situ surface reconstruction, forming the oxidized active catalyst that delivers an overpotential of 280 mV at 10 mA cm^-2, a Tafel slope of 70 mV dec^-1, and an impressive Faradaic efficiency of 90.1%. Our findings highlight how the deliberate spatial arrangement and chemical integration of distinct functional layers can unlock superior electrocatalytic behavior, offering design insights for next-generation water-splitting systems.