Titanate nanotubes as support of solid base catalyst

Modified titanate nanotubes with enhanced basicity were synthesized by the incipient wetness impregnation of sodium titanate nanotubes (Na-TNT) with basic cations (Mg2+, K+, Ba2+, Zn2+). The essential morphology and mesoporosity of the nanotubes were maintained, as well as the tri-titanate structure, although in some cases (Mg2+) ion exchange and intercalation reactions brought about some contraction of the rolled titanate layers. Basic sites were probed with CO2 adsorption microcalorimetry and infrared spectroscopy, revealing strong (Qads > 150 kJ mol−1), medium (150 < Qads < 120 kJ mol−1), and weak basic sites that were absent in Na-TNT. These sites could be identified correspondingly with IR bands for relevant carbonate and bicarbonate complexes. All modified TNT catalysts demonstrated high conversions for the COS and CS2 hydrolysis reactions at 553 K, confirming the presence of important basic sites.

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► Alkali-modified titanate nanotube catalysts maintain their morphology and structure.
► CO2 adsorption microcalorimetry, complemented with IR, show increase in surface basicity.
► Catalyst show reactivity for COS–CS2 hydrolysis, which is related to the degree of catalyst basicity.