Study of MgO and Pt/MgO Systems by XRD, TPR, and ¹H MAS NMR

Abstract

We studied changes in magnesium oxide upon rehydration under operating conditions similar to those used in the subsequent impregnation of a metal salt on its surface. The ensuing transformations were monitored by using the XRD, TPR, and 1H MAS NMR techniques. On the basis of the results, magnesium oxide (periclase phase) is rehydrated to magnesium hydroxide (brucite phase) and dehydrated back to periclase when the calcination temperature is raised to 600 °C. At this point, the transformation occurs simultaneously with changes in the textural and basic properties of the solid. Pt/MgO catalysts prepared by impregnation of magnesium oxide exhibit variable metallic and surface properties depending on whether Pt(NH3)4(NO3)2 or H2PtCl6 is used as the impregnating salt.

Glucose isomerisation into fructose over magnesium-impregnated NaY zeolite catalysts

“…XRD did not identify the presence of MgO (2θ = 37.0, 43.0, 62.4, 74.8 and 78.7° [43,44]) on the calcined zeolite resulting from the NaY zeolite impregnation with the magnesium salt ( Fig. 1).…”

Effect of the synthetic method of Pt/MgO in the hydrosilylation of phenylacetylene

“…The surface area value obtained is small for the three supports. An increase in the surface area is observed in all cases as a result of the thermal treatment of the precursors 15 . A significant change in pore diameter is observed after the thermal treatment at 500 o C in the impregnated calcined MgO as well as in the impregnated agglomerated MgO.…”

“…A significant change in pore diameter is observed after the thermal treatment at 500 o C in the impregnated calcined MgO as well as in the impregnated agglomerated MgO. It has been reported that during the thermal treatment of MgO in the range 400-600 o C, there is one point when the pore diameter tends to decrease 15 .…”

“…Since the 1990´s, magnesium oxide has been increasingly used as a support for catalysts. Platinum on MgO is an example of such a catalyst 15,16 . Some studies have been focused on the influence of the precursors or metal salt or solvent used in the synthesis of the catalysts 16 .…”

Effect of Heating Atmosphere and Alkali Metal Doping on the Acidic and Basic Sites of Magnesium Oxide

“…MgO can be doped with different chemicals to increase its basicity, activity and selectivity for different types of reactions [9]. T. Kanno et al [10] studied the effect of addition of alkali metals to MgO and reported that basicity of MgO increased with the addition of alkali metals.…”