Influence of oxygen backgrounds on hydrogen sensing with SnO₂ nanomaterials

The influence of different oxygen backgrounds on the sensing of hydrogen with SnO₂ nanomaterials was investigated and a model was proposed. It is based on two hydrogen reaction mechanisms at the surface of tin oxide that can take place simultaneously; the weight of each mechanism depends on the concentration of oxygen in the ambient atmosphere. In the absence of oxygen the adsorbed hydrogen builds surface donors (rooted hydroxyl groups). In the presence of oxygen the reaction between hydrogen and pre-adsorbed oxygen ions dominates. Due to the fact that this behavior is present for very different nanomaterials, the model probably describes a SnO₂ specific feature.