Morphology and size effects on the reduction of silver oxide by hydrogen

Abstract

The dependence of reactivity towards hydrogen on size and morphology was studied for silver oxide Ag2O microparticles. Morphological tuning of the microparticles, which appeared in a size range from 340 to 1400 nm, was achieved in a wet‐chemical synthesis approach. Thermogravimetric measurements allowed the determination of onset temperatures and reaction rates for reduction with gaseous hydrogen as reducing agent. The results reveal the high complexity of the Ag2O reduction process, on which both the surface to volume ratio as well as the facet dependent activity of the morphologies have great influence. Differential scanning calorimetry was employed to study reduction by hydrogen, desorbing from a hydrogen‐loaded palladium foil, showing great effect of contact area size on the reactivity.

Polymer-assisted in-situ thermal reduction of silver precursors: A solventless route for silver nanoparticles-polymer composites

“…S2). [46,48] Interestingly, when Ag 2 O (10 wt.%) was heated in presence of polymers, a sharp mass loss of about 1-2% was observed at a much lower temperature Similar mass loss profile was observed when Ag 2 O-PP mixture was analyzed in TGA. PP being a hydrophobic polymer, mass loss was in good agreement with the calculated value i.e.…”

“…Interestingly, when H 2 was used during the thermal reduction of Ag 2 O, a significant decrease in the E a (~60 kJ mol -1 ) was achieved which also decreased the reduction temperature to 140-150 °C. [47,48] Similar decrease in E a and decomposition temperature was also observed during the reduction of silver acetate. [41] Herein, a single-step solvent-less process for AgNP-polymer composite preparation is reported which combines the basic understanding of the thermal reduction mechanism of Ag precursors with the mild reducing environment of molten polymers.…”

Large-scale synthesis of polyhedral Ag nanoparticles for printed electronics

“…The reaction follows a surface driven mechanism where H 2 O 2 chemisorbs and reacts on the surface of Ag 2 O particles followed by reduction and growth of the pure Ag phase, like a reaction with a reducing gas. 23 On a broader view, the reaction proceeds through the following three stages:…”

Challenges in hydrogen quantification using Kelvin probe technique at different levels of relative humidity

“…Previous studies focussing on silver show that there is a dependency on the surface microstructure of Ag 2 O concerning the ability to reduce hydrogen. It was shown that the surface to volume ratio of the Ag 2 O crystals as well as the facet-dependent activity of the morphologies plays a role in the oxide reduction process via differences in the contact area size [32].…”