The effect of Pt and Ni loading on the catalytic performances of WO3/TiO2 for n-hexane reforming reactions: Scalable studies under industrial conditions

Abstract Herein, three catalyst composites, namely, unpromoted WO3/TiO2 (WTi), promoted 2.5% Pt/WO3/TiO2 (PtWTi) and 2.5% Ni/WO3/TiO2 (NiWTi), were prepared via wet impregnation of a TiO2 pellet with ammonium metatungstate, chloroplatinic acid hydrate or nickel nitrate hydrate salts as the precursors for W, Pt, or Ni, respectively. To estimate the effect of Pt and Ni addition on the catalytic properties of WTi, the PtWTi and NiWTi catalyst composites were investigated by in situ XPS, ex-situ BET and XRD, and the obtained results were compared with those obtained for unpromoted WTi. The catalytic activity of the catalyst composites was systematically evaluated for the reforming reactions of n-hexane (nC6) (hydroisomerization and hydrocracking). The BET surface area data show that Pt and Ni addition have no effect on the surface area before and after hydrogen activation. However, XPS measurements revealed that the addition of Pt and Ni endowed the catalyst with metallic sites. This effect results in an increase in the isomerization selectivity and decreased β-Scission cracking for the n-hexane reactions. However, NiWTi showed the best catalytic activity and stability for n-hexane reforming at lower activation/reaction temperatures of 623 K/548 K compared with 673 K/589 K for PtWTi.