... Journal of Catalysis. Volume 279, Issue 2, 25 April 2011, Pages 310–318. ... Ta 2 (OEt) 10 (III) (tantalum (V) ethoxide, 99+% Alfa Aesar) was used as a precursor for the preparation of the Ta 2 O 5 /TiO 2 catalyst to compare the catalytic activity with the Re catalysts. 2.2. ...