Multimetallic

Multimetallic is an adjective used in materials science and chemistry to describe substances that contain two or more metallic elements in significant proportions. These materials include alloys, intermetallic compounds, multimetallic nanoparticles, and high-entropy alloys. The term contrasts with monometallic systems that contain a single metal.

In solid-state materials, multimetallicity can be realized as random solid solutions, ordered intermetallics, or core–shell architectures where a shell or core consists of different metals. Bimetallic and trimetallic nanoparticles offer tunable surface composition and properties, while high-entropy alloys, typically five or more principal elements, exhibit high configurational entropy that can stabilize unusual combinations.

Synthesis methods vary: co-reduction and seed-mediated growth for nanoparticles; galvanic replacement, chemical vapor deposition, and electrochemical deposition; mechanical alloying and high-temperature melting for bulk alloys. Characterization relies on electron microscopy, X-ray diffraction, spectroscopy, and surface analysis to determine composition, phase, and structure.

Multimetallic systems exhibit synergistic effects that can modify electronic structure, adsorption energies, and catalytic activity beyond those of constituent metals. They often show enhanced stability, corrosion resistance, or strength, and enable tunable optical and magnetic properties, useful in sensing and imaging.

Common applications include catalysis (electrochemical and chemical), energy storage and conversion, and advanced electronics. Challenges include controlling phase formation and distribution, ensuring uniformity in nanoscale systems, toxicity and cost, and scaling synthesis for industrial use.