A comparative study of the WOx dispersion on Mn-promoted tungstated zirconia catalysts prepared by conventional and high-throughput experimentation

Abstract

Conventional and high-throughput experimentation (HTE) techniques were used for the synthesis, characterization, and catalytic testing of Pt/Mn–WOx–ZrO2 materials. The catalysts were prepared by surfactant-assisted coprecipitation and screened for catalytic activity in a multi-channel fixed bed (MCFB) micro-reactor for the hydroisomerization of n-hexane. Conventional coprecipitation route leads mainly to the segregation of the WO3 crystalline phase (XRD). On the other hand, the use of the automated HTE route allows the formation of catalysts with a highly dispersed WOx phase on the zirconia surface and a high surface area (60–100 m2/g) when calcined at 800 °C (N2 physisorption, XRD, Raman, UV–vis, HRTEM). These polytungstates with different coordination symmetry are accessible to the reactants and they lead to an increase in the catalytic activity and selectivity to the bi-ramified products (2,2-DMB and 2,3-DMB) in the n-hexane isomerization. In addition, it was found that the incorporation of Mn modifies the nanostructural properties of the tungstated zirconia favoring the catalytic activity of these materials.