monometallische

Monometallische, the German term for monometallic, describes materials or catalysts composed of a single chemical element, as opposed to alloys or multi-metal systems. The term is used across chemistry, catalysis, and materials science to denote uniform elemental composition and catalytic sites derived from one metal.

In catalysis, a monometallic catalyst consists of a single metal dispersed on a support or as nanoparticles. This contrasts with bimetallic or multi-metallic catalysts, where two or more metals introduce synergistic effects that can alter activity and selectivity. Monometallic systems can include noble metals such as platinum, palladium, gold, and rhodium, as well as base metals like nickel or cobalt.

Synthesis methods include impregnation onto porous supports, co-precipitation, deposition-precipitation, or colloidal synthesis, followed by reduction or calcination. The active phase may be nanoparticles with defined size or isolated atomic sites in single-atom catalysts. The performance depends on particle size, dispersion, support interactions, and oxidation state.

Applications span hydrogenation and dehydrogenation, oxidation, reforming, and various fine-chemical processes. Advantages of monometallic catalysts include simplicity, well-defined active sites, and easier characterization. Limitations include limited tunability of activity and selectivity compared to bimetallic systems, and susceptibility to sintering or poisoning.

In German-language literature, the term is monometallisch or monometallische; in English, monometallic is preferred. Overall, monometallic systems provide a foundational category in catalysis and materials science, serving as benchmarks and starting points for alloying strategies and site-specific studies.