Microstructured Au/Ni-fiber catalyst: Galvanic reaction preparation and catalytic performance for low-temperature gas-phase alcohol oxidation

The highly active and selective gold catalysts were successfully prepared by galvanically depositing Au onto a thin-sheet microfibrous structure consisting of 5 vol.% 8-μm Ni-fiber and 95 vol.% voidage, with high heat conductivity and good stability for the gas-phase oxidation of alcohols. The best catalyst was Au-4/Ni-fiber-300 (Au-loading: 4 wt%; calcined at 300 °C in air), being effective for oxidizing acyclic, benzylic, and polynary (1,2-propanediol) alcohols. For benzyl alcohol, the conversion of 95% was achieved with 99% selectivity to benzaldehyde within 660 h test at 250 °C, while a low ΔT of <10 °C between catalyst bed and reactor external wall was observed. Transformation of NiCl2 formed at Au galvanic deposition step into NiO was identified along with the low-temperature activity promotion. This suggests a special synergistic effect between NiO and Au particles, of which comprehensive understanding is particularly desirable.

The highly active and selective gold catalysts on nickel fiber, with excellent heat conductivity and stability, were successfully prepared by galvanic exchange reaction for effective gas-phase oxidation of alcohols. Transformation of NiCl2 formed at Au galvanic deposition step into NiO was identified, which contributes to the low-temperature activity promotion.Figure optionsDownload high-quality image (174 K)Download as PowerPoint slideHighlights
► We developed a novel Au/Ni-microfiber catalyst for gas-phase oxidation of alcohols.
► The gold was galvanically deposited onto sinter-locked 8-μm Ni-fiber net-work.
► The catalyst shows excellent activity, heat conductivity, and good stability.
► The NiCl2-to-NiO transformation promoted the catalytic activity significantly.