The effect of doping on the point of zero of charge of alumina

Interaction Forces on α-Alumina Surfaces with Coadsorbed Anionic Surfactant and Nonionic Polymer

“…The decay length is in good agreement with the theoretical Debye length (9.6 nm). The surface potential of α-alumina was positive, which was expected since the isoelectric point of α-alumina suspensions is about 9 and the surface hydroxyl groups on α-alumina are mostly protonated at pH 3.5 2 Normalized forces between α-alumina surfaces in aqueous SDS solutions containing 1 mmol dm -3 salt as background electrolyte at pH 3.5. …”

Determination of the Surface Isoelectric Point of Oxide Films on Metals by Contact Angle Titration

“…12 occurs at pH 5.3, as can be seen agreement with the values values of 8.7 to 9.2 reported by by fitting a third-order polynomial through the data. (A better a number of investigators (8,(38)(39)(40)(41) for the isoelectric fit resulted than with a second-order polynomial.) Thus, the point of bulk aluminum oxide (powders).…”

Relating Catalytic Activity of d0 Semiconducting Metal Oxides to the Fermi Level Position

“…16 Many metal oxides are semiconductors, and the type and concentration of majority charge carriers directly influence the acid− base properties. 17,18 Since doping can modify carrier concentration, quite a bit of attention has focused on adding altervalent elements to modify activity and selectivity. 14,19−21 However, the dopants can exert both chemical and electronic effects whose deconvolution is often difficult.…”

“…Transition metal oxides are used widely in the heterogeneous catalysis of gas-phase reactions such as alcohol oxidation, , selective reduction of NO x , , oxidative dehydrogenation of alkanes, and many others. − The acid–base properties of such materials often determine catalytic performance . Many metal oxides are semiconductors, and the type and concentration of majority charge carriers directly influence the acid–base properties. , Since doping can modify carrier concentration, quite a bit of attention has focused on adding altervalent elements to modify activity and selectivity. ,− However, the dopants can exert both chemical and electronic effects whose deconvolution is often difficult. Many laboratories have reported changes in reaction rate with doping level, but far fewer have demonstrated the systematic variation of reaction rate with carrier concentration. , Controlling this concentration in oxides is less straightforward than in other semiconductors such as Si and Ge, as not all dopant atoms are electrically active yet many native defects are.…”