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Pourbaix diagram of iron. [1] The Y axis corresponds to voltage potential. In electrochemistry, and more generally in solution chemistry, a Pourbaix diagram, also known as a potential/pH diagram, E H –pH diagram or a pE/pH diagram, is a plot of possible thermodynamically stable phases (i.e., at chemical equilibrium) of an aqueous electrochemical system.
While lists of noble metals can differ, they tend to cluster around gold and the six platinum group metals: ruthenium, rhodium, palladium, osmium, iridium, and platinum. In addition to this term's function as a compound noun , there are circumstances where noble is used as an adjective for the noun metal .
The and pH of a solution are related by the Nernst equation as commonly represented by a Pourbaix diagram (– pH plot).For a half cell equation, conventionally written as a reduction reaction (i.e., electrons accepted by an oxidant on the left side):
Marcel Pourbaix (16 September 1904 – 28 September 1998) was a Belgian chemist and pianist. [citation needed] He performed his most well known research at the University of Brussels, studying corrosion. [1] His biggest achievement is the derivation of potential-pH, better known as “Pourbaix Diagrams”.
Pourbiax diagrams will show the phases that a material will take in an aqueous environment, based on electrical potential and pH. The brain maintains a pH of around 7.2 to 7.4, and from the Pourbaix diagram of platinum [3] it can be seen that at around 0.8 volts Pt at the surface will oxidize to PtO 2, and at around 1.6 volts, PtO 2 will ...
The platinum-group metals [a] (PGMs) are six noble, precious metallic elements clustered together in the periodic table. These elements are all transition metals in the d-block (groups 8, 9, and 10, periods 5 and 6). [1] The six platinum-group metals are ruthenium, rhodium, palladium, osmium, iridium, and platinum.
The conditions necessary, but not sufficient, for passivation are recorded in Pourbaix diagrams. Some corrosion inhibitors help the formation of a passivation layer on the surface of the metals to which they are applied. Some compounds, dissolved in solutions (chromates, molybdates) form non-reactive and low solubility films on metal surfaces.
Potential decreases as the solution becomes more basic and this relationship is described by the Pourbaix Diagram. [6] All the above parameters are responsible for controlling side product release. [2] [6] [11] Side product formation negatively affect the bath by poisoning the catalytic site, and disrupt the morphology of the metal nanoparticle.