Properties and Bifunctional Catalytic Activity of Niobium-Doped Silica-Titania: Effect of Phosphoric Acid Treatment

Siew Ling Lee, Jamilah Mohd Ekhsan, Chui Min Ling


The effect of phosphoric acid treatment on the physical-chemical properties and catalytic activity of the niobium-doped silica-titania bifunctional catalyst was investigated. As part of the synthesis procedure to produce xPO4/Nb/TiO2-SiO2, different concentrations of phosphoric acid (H3PO4) were used (x= 0, 0.05, 0.10, 0.15, 0.20, 0.25 M). As shown by XRD analysis, the samples synthesized using 0–0.20 M H3PO4 were in amorphous form, as featureless diffractograms were obtained, indicating the PO4 groups were dispersed homogeneously on the surface of Nb doped SiO2-TiO2. Due to the increased concentration of acid, other compounds were formed in the samples by reactions between PO4 and Nb and/or Ti. Additionally, UV-Vis DRS results indicated that the presence of the PO4 group accelerated the transformation of hydrated tetrahedral Ti species into isolated tetrahedral Ti species. An experimental investigation of the catalytic performance of the catalyst was conducted using 1,2-epoxyoctane as an oxidant for the epoxidation of 1-octene to 1,2-octanediol. It has been demonstrated that H3PO4 treatment was essential for oxidative and acidity active site formation. The current research findings strongly suggested that Nb-doped TiO2-SiO2 treated with 0.2 M H3PO4 was the most effective bifunctional catalyst in generating 1,2-octanediol.


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Siew Ling Lee (Primary Contact)
Jamilah Mohd Ekhsan
Chui Min Ling
Lee, S. L., Ekhsan, J. M., & Ling, C. M. (2022). Properties and Bifunctional Catalytic Activity of Niobium-Doped Silica-Titania: Effect of Phosphoric Acid Treatment. Science and Technology Indonesia, 7(4), 455–460.

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