Multimetal

Multimetal refers to a material that contains more than one metallic element. In materials science, the term covers alloys, intermetallic compounds, and multimetallic nanostructures, as opposed to monometallic materials that consist of a single metal. Multimetal systems can exhibit properties that differ from their constituent metals due to changes in structure, bonding, and electronic properties.

Alloys are the most common form of multimetal systems and can be homogeneous solid solutions or intermetallic compounds with defined stoichiometries. Examples include stainless steel (iron-chromium-nickel) and brass (copper-zinc). Intermetallic compounds, a subset of multimetals, feature ordered crystal structures and fixed compositions, which can give rise to unique mechanical or thermal behaviors.

At the nanoscale, multimetallic nanoparticles or clusters combine two or more metals to achieve synergistic effects such as altered adsorption energies, enhanced catalytic activity, selectivity, and stability. Synthesis methods include co-reduction, seed-mediated growth, galvanic replacement, and mechanical alloying.

Applications of multimetal systems span catalysis, energy storage, electronics, and structural materials. In catalysis, bimetallic and trimetallic systems often outperform single-metal catalysts in reactions like hydrogen evolution, oxygen reduction, and CO2 reduction. In structural applications, multi-element alloys can offer improved strength, hardness, or corrosion resistance. Practical considerations include phase stability, potential segregation or precipitation, cost, and the complexity of phase diagrams that govern performance.