A major drawback of state‐of‐the‐art proton exchange membrane fuel cells is the CO poisoning of platinum catalysts. It is known that CO poisoning is reduced if platinum alloys are used, but the underlying mechanism therefore is still under debate. We study the influence of dopant atoms on the CO adsorption on small platinum clusters using mass spectrometry experiments and density functional calculations. A significant reduction in the reactivity for Nb‐ and Mo‐doped clusters is attributed to electron transfer from those highly coordinated dopants to the Pt atoms and the concomitant lower CO binding energies. On the other hand Sn and Ag dopants have a lower Pt coordination and have a limited effect on the CO adsorption. Analysis of the density of states demonstrates a correlation of dopant‐induced changes in the electronic structure with the enhanced tolerance to CO poisoning.

Bulk SiO₂-PbF₂ oxyfluoride glasses co-doped with dispersed luminescent Ag nanoclusters and Tm³⁺ ions have been prepared by conventional melt-quenching method. Luminescence from 400 to 900 nm has been excited in this glass by UV light from 340 to 400 nm. The prepared glass has potential for application as a low cost glass phosphor in Hg-free white light generation in UV-driven devices, flexible monitors and as down-shifting layers for enhanced solar cells. Co-doping with Tm³⁺, which has an absorption band ³H₆→¹D₂, affects the tint of the total Ag-Tm³⁺ white emission band of this glass by changing the excitation wavelength to about 365 nm, which is almost the same wavelength as that of a commercial LED.

Photoabsorption spectra of gas phase Au_n⁺ and Au_n−1Pd⁺ (13 ≤ n ≤ 20) clusters were measured using mass spectrometric recording of wavelength dependent Xe messenger atom photodetachment in the 1.9–3.4 eV photon energy range. Pure cationic gold clusters consisting of 15, 17, and 20 atoms have a higher integrated optical absorption cross section than the neighboring sizes. It is shown that the total optical absorption cross section increases with size and that palladium doping strongly reduces this cross section for all investigated sizes and in particular for n = 14–17 and 20. The largest reduction of optical absorption upon Pd doping is observed for n = 15.