Zinc mediated crystalline assembly of gold nanoclusters for expedient hydrogen storage and sensing

Abstract

Programmed assembly of "few atom" quantum clusters may offer superior physicochemical properties of the new material in comparison to the constituents. We report the formation of a luminescent crystalline inorganic complex, consisting of Zn²⁺ ions and L-histidine plus mercaptopropionic acid stabilized Au₁₄ nanoclusters, with a complexation constant of (9.7 ± 6.6) × 10⁶ M⁻¹. Analytical investigations, supported by computational modelling, indicated the hexagonal structure of the crystal. The crystalline complex exhibited superior luminescence in comparison to ligand stabilized gold nanoclusters. Importantly, the complex stored hydrogen reversibly at room temperature, accompanied by change in the luminescence playing the role of sensing. The hydrogen adsorption capacity of the complex was determined to be 0.244 mM per gram of the complex at 20 °C and 20 bar.