Acetone to isobutene conversion on ZnxTiyOz: Effects of TiO2 facet

• Published in: Journal of catalysis 2022-06, Vol.410, p.236-245
• Main Authors: Li, Houqian, Hurlock, Matthew J., Sudduth, Berlin, Li, Junrui, Sun, Junming, Zhang, Qiang, Wang, Yong
• Format: Article
• Language: English
• Subjects: Acetone; DRIFTS; Facet; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Mechanism; TiO2; ZnxTiyOz
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2022.03.031

[Display omitted] •ZnxTiyOz with well-defined surface were synthesized by liquid-phase grafting using (1 0 1) or (0 0 1) facet dominant anatase.•Site requirements of acetone to isobutene reaction at molecular level were studied by faceted mixed metal oxides.•The bridging OHs with rapid proton transfer efficiently stabilize a transition state in the acetone to isobutene conversion. Liquid-phase chemical grafting method was used to graft Zn onto TiO2 with preferentially exposed (101) or (001) facet. The obtained ZnxTiyOz materials were characterized using various techniques (e.g., XRD, Raman, DRIFTS etc.) and evaluated for the acetone-to-isobutene reaction. It was found that over TiO2 (001), both terminal and bridging hydroxyls were readily titrated by Zn deposition, whereas a substantial amount of bridging hydroxyls on TiO2 (101) remained. Although dominant Zn-O-terminated surface was obtained on two ZnxTiyOz samples, bridging hydroxyls with high H-D exchange reactivity were observed on ZnxTiyOz (101) compared with ZnxTiyOz (001). The bridging hydroxyls showing rapid proton transfer efficiently stabilizes a transition state of diacetone alcohol intramolecular rearrangement for isobutene production as opposed to the diacetone alcohol dehydration.