Efficient CO (carbon monoxide) oxidation using gold catalysts supported on WO3/titanate protonated nanotubes. (July 2019)

• Record Type: Journal Article
• Authors: Camposeco, R.; Castillo, S.; Hinojosa-Reyes, M.; Nava, N.; Zanella, R.
• Is Part Of: Materials research bulletin. Volume 115(2019)
• Page Start: 247
• Page End: 256
• Publication Date: 2019-07
• Subjects: Titanate protonated nanotubes -- Deposition–precipitation -- Sol–gel -- CO oxidation -- Gold nanoparticles; Materials -- Periodicals; Crystal growth -- Periodicals; Matériaux -- Périodiques; Cristaux -- Croissance -- Périodiques; Crystal growth; Materials; Periodicals; 620.11
• DOI: 10.1016/j.materresbull.2019.04.004
• Languages: English
• ISSNs: 0025-5408

Abstract

Graphical abstract: Highlights: Gold improves the WO3 interaction with titanate nanotubes, reducing W 5+ species. XPS revealed the presence of Au 0, W 5+ and W 6+, promoting CO oxidation species at low temperatures. The 2Au-3WO3 /NT catalyst showed resistance to deactivation compared to 2Au/NT catalysts. Under hydrogen treatment, the 2Au-3WO3 /NT catalyst displayed remarkable catalytic activity. Tungsten preserved the tubular structure of NT and prevented gold agglomeration at up to 400 °C. Abstract: WO3 /titanate protonated nanotubes used to disperse gold nanoparticles were prepared by the deposition-precipitation with urea method and tested in CO oxidation reaction. Remarkably enhanced CO oxidation activity was achieved with the addition of gold nanoparticles with respect to WO3 /NT and Au/NT catalysts. XPS and H2 /TPR showed that when the samples were activated at 400 °C under hydrogen treatment, gold was present in the metallic Au 0 form and tungsten as W 5+ and W 6+ species; likewise, the addition of tungsten to the tubular morphology led to the formation of vacancies and new adsorption sites, preserving the structure at up to 400 °C. The interaction between WO3 and the titanate nanotubes was improved by adding gold nanoparticles with sizes around 1 and 3 nm under hydrogen treatment, increasing the content of reduced W 5+ species that promoted the CO oxidation at low temperatures. The 2Au-3WO3 /NT catalyst was active from 0 °C and showed temporary stability at room temperature.