Dynamically Dual-Center Coupled Synergistic Catalysis for Highly Efficient Oxygen Reduction.

Area of Science:

• Heterogeneous catalysis
• Electrocatalysis
• Materials science

Background:

• The oxygen reduction reaction (ORR) is kinetically limited by intermediate adsorption and competing pathways.
• Conventional catalysts struggle to control O-O bond cleavage and hydrogen peroxide (H2O2) desorption simultaneously.
• Divergent reaction pathways lead to inefficient 4e- or 2e- pathways, hindering ORR performance.

Purpose of the Study:

• To overcome kinetic limitations in the ORR by developing a novel catalytic mechanism.
• To engineer binary-component interfaces that enable dynamic dual-center coupled synergy (DCCS).
• To establish a new design principle for heterogeneous catalysis by molecularly scheduling reaction pathways.

Main Methods:

• Fabrication of precisely engineered PdRh-Pt nanosheet binary-component interfaces.
• Multidimensional in situ synchrotron radiation spectroscopy to probe reaction intermediates and pathways.
• Theoretical studies (e.g., DFT) to elucidate the DCCS catalytic mechanism and kinetics.

Main Results:

• The DCCS mechanism, primarily occurring at PdRh sites, activates the 4e- pathway.
• Pt centers facilitate selective reduction of *OOH to *O and H2O2, while PdRh sites promote H2O2 migration and dissociation.
• A six-fold increase in turnover frequency was observed compared to commercial Pt/C, alongside exceptional 200-hour stability in Zn-air batteries.

Conclusions:

• The engineered PdRh-Pt interfaces enable DCCS catalysis, redirecting divergent pathways to a singular 4e- dominant route.
• Interfacial kinetic synergy effectively breaks the kinetics trade-off in ORR, enhancing catalytic efficiency.
• This study presents a new design principle for advanced catalysts by controlling reaction pathways at the molecular level.