Topic
Valency
About: Valency is a research topic. Over the lifetime, 1632 publications have been published within this topic receiving 26141 citations.
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5 citations
TL;DR: In this paper , the authors demonstrate that the strong metal-support interaction between Ir and ATO can paradoxically deactivate Ir/ATO structures when synthesizing them using the polyol process.
Abstract: Only a few materials can remain undissolved under working conditions for the oxygen evolution reaction (OER) in acidic media, which limits the choice of catalysts and supports. One of the practical catalyst/support candidates is IrOx/Sb:SnO2 (Ir/ATO) because both components are thermodynamically stable under low-pH anodic conditions. Moreover, between Ir and ATO, a strong metal–support interaction is present, thereby allowing for long-lasting OER activity unless the support degrades. However, we demonstrate that the strong interaction can paradoxically deactivate Ir/ATO structures when synthesizing them using the polyol process. We reveal that the strong interaction in the presence of polyol at elevated temperatures can cause the reduction of the Sb dopant to zero-valency. Findings show that the varied oxidation state of the dopant decreases the electrical conductivity of the Ir/ATO, impeding the electron transfer through the support, hence deteriorating electrocatalytic activity toward the OER.
5 citations
TL;DR: In this paper, mixed valency solid solutions of formula Cr 1 − x Nb x WO 4 have been prepared at 1200°C and two phases have been identified at room temperature by X-ray diffraction.
5 citations
TL;DR: In this paper, it is shown that the chemist's concept of valency can be put in quantum mechanical language, which opens up possibilities of new applications which are briefly reviewed here.
Abstract: It is shown that the chemist's concept of valency can be put in quantum mechanical language. Such a quantification of valency opens up possibilities of new applications which are briefly reviewed. Valency is related to the equilibrium geometry of the molecule through a maximum valency principle. This principle, combined with the idea of molecular orbital valencies, provides a theoretical foundation for the well known Walsh diagrams. Valency can be used as an index of chemical reactivity and valency changes in a reaction can be used to determine the radical nature of intermediates and transition states as well as to indicate the allowed or forbidden nature of reaction paths. Molecular strain may be related to the loss of sigma valency.
5 citations
5 citations