A study on Al and Al–Ce–Fe pillaring species and their catalytic potential as they are supported on a bentonite

This work describes the synthesis and characterization by XRD of pillaring species in solid state, obtained from Al or Al–Ce–Fe polyhydroxocationic solutions, the modification of a bentonite via pillaring by ionic exchange with such solutions and the catalytic activity of the pillared clays in the phenol oxidation reaction in diluted aqueous medium with hydrogen peroxide. Results indicate the formation of boehmite from the Al3+ polyhydroxocationic solution and the presence of three different crystalline structures (boehmite, α-Fe2O3 and CeO2) into the solid synthesized from the Al–Ce–Fe polyhydroxocationic solution. The EPR analysis confirms the formation of iron oxide particles and the likely inclusion of isolated Fe3+ species into the alumina matrix. On the other hand, the clay modified with Al–Ce–Fe is a very active (100% of phenol conversion in the first hour of reaction) and selective (55% of selectivity to CO2) catalyst in the total oxidation of phenol, at 20 °C and atmospheric pressure.

Graphical abstractThis work describes the synthesis and characterization by XRD of pillaring species in solid state, obtained from Al or Al–Ce–Fe polyhydroxocationic solutions, the modification of a bentonite via pillaring and the catalytic activity of the pillared clays in the total oxidation reaction of phenol. Results indicate the formation of boehmite from the Al3+ polyhydroxocationic solution and the presence of three different crystalline structures (boehmite, α-Fe2O3 and CeO2) into the solid synthesized from the Al–Ce–Fe polyhydroxocationic solution.Figure optionsDownload full-size imageDownload as PowerPoint slide