Highly porous Ce-W-TiO2 free-standing electrospun catalytic membranes for efficient de-NOx via ammonia selective catalytic reduction

Highly porous Ce-W-TiO₂ free-standing nanofibrous membranes (FSM) are fabricated via electrospinning techniques to serve as NOx-SCR catalysts. The precursor of the ceramic nanofibers (sol-gel solution) is co-electrospun with a poly(vinyl alcohol) (PVA) water solution. PVA integration into FSM is proven to avoid excessive bending of the nanofibers, and to prevent mechanical failure of the final ceramic nanofibrous structure. This is demonstrated to be associated with PVA higher thermal stability compared with the other organic additives. 3D tomography reconstruction indicates a resulting ceramic membrane with a great open and interconnected porosity of ca. 96%. The catalytic characterization, performed at the best working conditions (in absence of H₂O and SO₂), indicates the amorphous FSM as the best performing catalytic membrane. Superior catalytic performances for the developed FSM, over the nanofibers and the nanoparticles catalysts are proven, as a result of superior surface, morphological, and structural features. Long-term stability (120 h) and reproducibility (over 5 cycles) of the FSM are also demonstrated.