Synergistic Interactions and Structural Engineering of Bimetallic Catalysts for Electrocatalytic Energy Conversion

Abstract

Bimetallic catalysts represent a transformative platform for transcending the linear scaling relationships (LSRs) inherent to monometallic surfaces, enabling superior efficiency in sustainable energy conversion. This review establishes a universal synergistic framework linking fundamental electronic modulation to macroscopic catalytic performance. We systematically elucidate four core synergistic mechanisms: site enrichment, electronic structure modulation (including d-band center shifts, charge redistribution, and orbital hybridization), lattice strain/geometric distortion, and interfacial polarity-induced intermediate activation. Based on structure-performance relationships, we categorize bimetallic systems into alloys, compound-based composites, metal-metal oxides, dual-atom catalysts (DACs), layered double hydroxides (LDHs), and metal-organic frameworks (MOFs). Crucially, this review highlights the often-overlooked aspect of dynamic structural reconstruction under operating conditions, identifying that the "true" active phases frequently evolve from pre-catalysts during electrolysis. Highlighting recent breakthroughs in CO2 reduction, ammonia/urea synthesis, and water splitting (HER/ORR/OER), we dissect how dual-metal sites optimize multi-electron transfer pathways via tandem catalysis and spinstate regulation. Finally, we outline critical perspectives on data-driven rational design, high-spatiotemporal-resolution operando spectroscopy, and strategies to bridge the gap toward industrial-scale current densities, providing a roadmap for the next generation of bimetallic electrocatalysts.