Influence of the incorporation of Fe and Mn on the nanostructure and reactivity of catalysts based on tungstated zirconia

Unraveling the Effects of Fe and Mn Promoters on the Tungstated Zirconia Catalyst: A Dft Study

“…We would like to highlight that only in the Fe-WO 3 /ZrO 2 system, the dopant shows a preference to be incorporated into the zirconia lattice, rather than at the interface between the two oxides or on top of the tungsten oxide clusters. In previous experimental works, the lattice parameters of the tetragonal zirconia were found to increase scarcely upon the addition of Mn or Fe [21], suggesting that at least a portion of the promoters would be integrated interstitially into the zirconia lattice. We must emphasize that our DFT calculations give information on the thermodynamic stability of different species, location or conformers, and these isomers are predicted to be present in an experimental sample with different relative abundance.…”

“…Experimentally, it was reported that adding small amounts of metal promoters (Fe or Mn) increases alkene isomerization yield with respect to pure WZ [18,21]. Such catalytic boosting depends strongly on the metal concentration; the isomerization conversion is increased as the metal concentration increases, until reaching a maximum, and then the conversion decreases for higher metal concentrations.…”

“…The catalytic performance of sulfated and tungstated zirconia catalysts can be boosted by incorporating diverse promoters, such as gallium, aluminum, iron or manganese [11][12][13][14][15][16][17][18][19][20][21][22][23]. SZ doped with Fe and Mn, for example, catalyzes isomerization reactions two to three orders of magnitude faster than undoped SZ [15,16,20,22].…”

“…SZ doped with Fe and Mn, for example, catalyzes isomerization reactions two to three orders of magnitude faster than undoped SZ [15,16,20,22]. Regarding WZ, several works have shown that the incorporation of Fe and Mn improves the paraffin isomerization activity of these catalysts [13,14,[17][18][19]21,23,24]. Nevertheless, as in the SZ case, the nature of the promoting effect of these metals remains highly debated.…”

“…Hernández-Pichardo et al carried out several experimental studies on the WZ promoted with Fe and Mn [17,18,21,24]. Their works suggested that Fe 3+ and Mn 3+ cations modify the interaction of the WO x species with the support.…”